INTERNSHIP REPORT AT SANJEN HEP 2019

KATHMANDU UNIVERSITY
SCHOOL OF ENGINEERING
DEPARTMENT OF CIVIL AND GEOMATICS ENGINEERING

REPORT
ON
INTERNSHIP ACTIVITY

At
Sanjen Hydroelectric Project
Chilime VDC, Rasuwa

Submitted By:
Rushit Shrestha (019035-15)
Abhay Suwal (019041-15)
Ashish Tamang (019043-15)

Submitted To:
Department of Civil Engineering
And
Chilime Engineering and Services Company Ltd. (ChesCo)
Kapan Marg, Kathmandu

June 2019
 INTERNSHIP REPORT AT SANJEN HEP 2019

ACKNOWLEDGEMENTS

We would like to express our heartfelt gratitude to Associate Prof. Dr. Prachand Man
Pradhan, Head of Department of Civil Engineeringand to our supervisor and lecturer, Prof.
Dr. Ing. Ramesh Kumar Maskey, for providing us this opportunity to express our skill and
knowledge about hydropower engineering by allowing us to enroll as interns in hydropower
projects. We would like to thank him for his constant availability, guidance, encouragement
and continuous support along the entirety of this period.

We would also like to thank Mr. Prajesh Bikram Thapa, CEO of Chilime Engineering and
Services Company Ltd. (ChesCo) for providing us necessary accommodation, fooding, and
transportation facilities during our internship period and also for providing the required
support and assistance through which our internship could be completed successfully.

We are very grateful to Er. Triratna Maharjan, Resident Engineer (SanjenHEP), Er.
Bikash Bajracharya, Interim Resident Engineer (SanejnUpper HEP) and to our supervisors
Er. Baburam Poudel,Senior Engineer Power House, Subash Manandhar, Overseer Power
House, Er. Pratik Bhatta, Senior Engineer Tunnel, Mr. Nabin Osti, Senior Geologist, Er.
Prithvi Dhwoj Khadka for providing us assistance and guidance during the entirety of our
internship period.

Finally we would like to thank all the engineers, overseers, and staffof ChesCo for providing
us guidance and support during our internship period both during our time in the site as well
as in the office, also we would like to thank the engineers, geologist and staff of Tundi
Construction (Pvt.) Ltd., contractor for Civil works of SHEP and electromechanical works
of both SHEP and SUHEP, and Bajra Guru Construction Co. Pvt. Ltd., contractor for civil
works of SUHEP, for providing assistance along the internship period. We are very grateful
to everyone who has provided us their valuable time and suggestion during the entirety of the
internship period which has helped immensely for the completion of our internship.

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 INTERNSHIP REPORT AT SANJEN HEP 2019

ABSTRACT

This document finalizes the completion of internship at Sanjen HEP, under the supervision
ofChilime Engineering and Services Company Ltd. (ChesCo) and Department of Civil
Engineering of Kathmandu University for the completion of course of Civil Engineering
Program. The 1st part of our internship comprised of site work in SHEP and SUHEP whereas
the latter part comprised of office work.

Sanjen Hydroelectric Project is located in Chilime VDC of Rasuwa District. This project in
whole comprises of two hydroelectric projects; namely, Sanjen (Upper) Hydroelectric Project
(14.8 MW) and Sanjen Hydroelectric Project (42.5 MW) in cascade.

During our internship period we had the opportunity to visit and study both SHEP and
SUHEP, but this document is focused mainly upon Sanjen Hydroelectric Project(42.5 MW).
Our internship comprised of 4 weeks of site work and 2 week of office work. During the
duration of site visit construction of power house in SHEP and SUHEP was going on,
construction of headrace tunnel and penstock tunnel was going on for SHEP, using drill and
blast method, and construction of headworks at Chhupchung Khola at Simbu, to draft 0.5m 3/s
discharge for SHEP, was going on. Works including lab tests, field test were also carried out
and visit to nearby hydropower project was done. Office works included study of report,
preparation of bar bending schedule, bill of quantities, quantity work out and rate analysis for
tail race of SHEP, design of drainage system for access road, quantity work out for access
road gabion, topographic map preparation for catchment area calculation and for hydrological
study of Chhupchhung Khola.

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 INTERNSHIP REPORT AT SANJEN HEP 2019

EXECUTIVE SUMMARY

This is an internship report on a 6 weeks long internship program successfully completed

under the supervision of Chilime Engineering and Services Company Ltd. (ChesCo) and
Department of Civil Engineering of Kathmandu University in Sanjen Hydroelectric Project.
This report contains detail of activities performed during the 6 weeks.

First four weeks of our internship was completed in the project site of SHEP in Chilime
VDC of Rasuwa District. During the time which construction of powerhouse, headworks,
head race and penstock tunnel were being carried out. And the final two weeks were spent
performing office work, including report study, preparation of bar bending schedule, bill of
quantities, quantity work out and rate analysis for tail race of SHEP, design of drainage
system for access road, quantity work out for access road gabion, topographic map
preparation for catchment area.

This report has been divided into six chapters. The first chapter deals with the introduction
part of this report which presents the objectives and scopes of the internship program as well
as brief about the Hydroelectric Project where the internship has been carried out i.e. Sanjen
Hydroelectric Project. The second chapter deals with the component of the HEP. This chapter
also includes brief of the construction processes that were being carried out such as tunnel
construction and concreting in the Power house with some of the problems faced in them.
Third chapter of this report presents about the construction equipments that were being used
for the construction of the HEP. Chapter four deals with quality control and assurance test
that were carried out which included tests for concrete and field density test. The sixth
chapter includes information about visit to a nearby HEP, Rasuwagadhi HEP. The last
chapter deals with the office work that has been carried out during the last two weeks of our
internship program.

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INTERNSHIP REPORT AT SANJEN HEP 2019

ABBREVIATIONS

% percentage
⁰ degrees
AC Alternating Current
amsl Above mean sea level
avg Average
b Breadth
BOOT Build Own Operate Transfer
BBS Bar Bending Schedule
cc Cubic centimeter
CEO Chief Executive Officer
ChesCo Chilime Engineering and Services Company Ltd.
cm Centimeter
cm2 Square centimeter
cumecs Cubic meter per second
d/s downstream
DHM Department of Hydrology and Meteorology
Dr. Doctor
E Easting
EDV Energy Dissipating Valve
e.g. example
Er. Engineer
etc et cetera
fck Characteristic Strength
FDC Flow duration curve
Gm Gram
GoN Government of Nepal
GWh Gigawatts hour
H Height
HEP Hydroelectric Plant
H.G Hydraulic gradient
HDPE High density polyethlene
HP Horse power
kg kilogram
km kilometer
km2 square kilometer
kN Kilo Newton
KU Kathmandu University
kV kilovolt
kWh kilowatts hour
kWhr kilowatt hour
l Length
ln logarithm
Ltd limited
m meter
M Magnitude
m/s meter per second

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INTERNSHIP REPORT AT SANJEN HEP 2019

m3 cubic metres
m3/s cubic metres per second
MCT Main Central Thrust
MDD Maximum Dry Density
mm millimeter
MPa Mega Pascal
MSL Mean Sea Level
MVA Mega Volt Ampere
MW Megawatt
MWI Monsoon wetness index
N Northing
NEA Nepal Electricity Authority
No. Number
Nos. Numbers
NRs Nepali Rupees
O &M Operation and Maintenance
OMC Optimal Moisture Content
PCC Plain Concrete Cement
Pg Page number
PH Powerhouse
PVC Polyvinyl chloride
Pvt Private
Q Discharge
RoR Run-off-River
rpm revolution per minute
SHEP Sanjen Hydro Electric Project
SUHEP Sanjen Upper Hydro Electric Project
sq. km square kilometer
T Time
u/s upstream
VDC Village Development Committee
WECS Water and Energy Commission Secretariat
Wt. Weight
Yrs years

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 INTERNSHIP REPORT AT SANJEN HEP 2019

CONTENTS
Abstract......................................................................................................................................2
Executive summary....................................................................................................................3
Abbreviations.............................................................................................................................4
Chapter 1..................................................................................................................................14
Introduction..............................................................................................................................14
1.1. Overview of Internship..............................................................................................14
1.2. Objectives and Scopes...............................................................................................14
1.3. Project Background...................................................................................................15
1.4. Project Features.........................................................................................................18
1.5. Salient Features.........................................................................................................20
1.5.1. Salient Features of Sanjen Hydroelectric Project...............................................20
1.5.1 Comparison between SUHEP and SHEP...........................................................22
Chapter 2..................................................................................................................................23
Components of the project.......................................................................................................23
2.1. Project Layout...........................................................................................................23
2.2 Headworks.................................................................................................................24
2.2.1 Tailrace Canal and Forebay with side channel spillway....................................24
2.2.2 Feeder Canal from Chhupchung Khola..............................................................25
2.2.3 Feeder Canal from Chhupchung Khola..............................................................25
2.2.4 Weir of Chhupchung Khola...............................................................................25
2.3 Head Race..................................................................................................................28
2.3.1 Inlet Portal of Headrace Tunnel.........................................................................28
2.3.2 Head Race Tunnel..............................................................................................28
2.3.3 Rock Trap...........................................................................................................29
2.3.4 Surge Shaft.........................................................................................................29
2.3.5 Valve Chamber...................................................................................................30
2.3.6 Penstock Tunnel.................................................................................................31
2.3.7 Adit Tunnel........................................................................................................32
2.3.7.1 Adit 1..........................................................................................................32
2.3.7.2 Adit 2..........................................................................................................32
2.4 Tunnel and it’s construction......................................................................................32

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2.4.1 Drilling...............................................................................................................33
2.4.2 Charging.............................................................................................................33
2.4.3 Stemming...........................................................................................................34
2.4.4 Detonation..........................................................................................................34
2.4.5 Ventilation..........................................................................................................34
2.4.6 Mucking.............................................................................................................34
2.4.7 Scaling................................................................................................................34
2.4.8 Geological Mapping...........................................................................................35
2.4.9 Installation of Support........................................................................................35
2.4.10 Excavation for incline in penstock.....................................................................37
2.4.11 Rock Support......................................................................................................37
2.4.11.1 Rib Support.................................................................................................37
2.4.11.2 Backfilling..................................................................................................38
2.4.11.3 Shotcreting..................................................................................................38
2.4.11.4 Invert Concrete and Concrete Lining..........................................................39
2.4.11.5 Rock Bolts...................................................................................................39
2.4.11.6 Grouting......................................................................................................39
2.4.12 Problems encountered during Tunneling...........................................................40
2.4.12.1 Seepage.......................................................................................................40
2.4.12.2 Over break...................................................................................................41
2.4.12.3 Lack of concrete padding for rock bolt pull out test...................................41
2.5 Surface Penstock.......................................................................................................42
2.6 Powerhouse................................................................................................................42
2.6.1 Mass Concreting.................................................................................................43
2.7 Generator Hall...........................................................................................................46
2.8 Control room.............................................................................................................46
Chapter 3..................................................................................................................................47
Construction Equipments.........................................................................................................47
3.1. Grouting Pump..........................................................................................................47
3.2. Hydraulic Excavator..................................................................................................47
3.3. Concrete Batching Plant............................................................................................48
3.4. Transit Mixer.............................................................................................................49
3.5. Sand Washing Plant...................................................................................................49

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3.6. Aggregate Crushing Plant..........................................................................................50

3.7. Concrete Pump..........................................................................................................50
3.8. Single Drum Vibratory Roller...................................................................................51
3.9. Alimak.......................................................................................................................51
3.10. Wheel Loader.........................................................................................................52
Chapter 4..................................................................................................................................53
Quality Control/AssuranceTests..............................................................................................53
4.1. Trial Mix of Concrete................................................................................................53
4.2. Compressive Strength Test........................................................................................55
4.3. Concrete Slump Test.................................................................................................63
4.4. Field Density Test......................................................................................................65
Chapter 5..................................................................................................................................68
Office Work.............................................................................................................................68
5.1. Introduction...................................................................................................................68
5.1.1. Detail Project Report (DPR) Study........................................................................68
5.1.1.1. Objective of DPR............................................................................................68
5.1.1.2. Contents in DPR..............................................................................................68
5.1.1.3. Importance of DPR.........................................................................................69
5.1.2. Technical Specification Study................................................................................69
5.1.2.1. Principle of writing Technical Specification...................................................69
5.1.2.2. Proper writing of specification........................................................................70
5.1.2.3. Importance of Technical Specification...........................................................71
5.1.3. Quantity Workout...................................................................................................71
5.1.3.1. Excavation for tail race of SUHEP.................................................................71
5.1.4. Bar Bending Schedule............................................................................................71
5.1.4.1. Importance of Preparing Bar Bending Schedule.............................................72
5.1.4.2. General guidelines to be followed in preparing BBS......................................72
5.1.4.3. Bar Bending Schedule User............................................................................72
5.1.5. Preparation of Topographic Map...........................................................................73
5.1.5.1. Introduction.....................................................................................................73
5.1.5.2. Procedure.........................................................................................................73
5.5.3. Plotting the Sample Points.....................................................................................74
5.5.4. Drawing Contours and Cross Sections...................................................................74

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5.1.6. Design of Drainage System....................................................................................74

5.1.6.1. Design process according to shape of drainage..............................................74
5.1.7. Catchment Area Calculation..................................................................................76
5.1.8. Hydrological Study................................................................................................76
5.1.8.1. WECS/DHM method......................................................................................76
5.1.8.2. MIP (Medium Irrigation Project) Method.......................................................76
5.1.8.3. CAR (Catchment Area Ratio) Method............................................................77
5.1.9. Preparation of Bill of Quantity (BOQ) and Rate Analysis....................................78
5.1.9.1 Bill of quantities (BOQ)...................................................................................78
5.1.9.2. Rate analysis:......................................................................................................78
5.1.10 Flood frequency analysis....................................................................................79
5.1.10.1 Gumbel’s distribution.................................................................................79
5.1.10.2 Log Pearson type III distribution................................................................80
5.1.10.3 Log normal distribution..............................................................................82
Chapter 6..................................................................................................................................83
Field Visit.................................................................................................................................83
6.1. Introduction...............................................................................................................83
6.2. Salient Features.........................................................................................................83
Project Details..................................................................................................................83
Hydrology........................................................................................................................83
Headworks........................................................................................................................83
Gravel Trap......................................................................................................................84
Desander...........................................................................................................................84
Headrace Tunnel..............................................................................................................84
Surge Tank.......................................................................................................................84
Penstock Pipe...................................................................................................................84
Powerhouse Cavern..........................................................................................................85
Transformer Cavern.........................................................................................................85
Tailrace Tunnel................................................................................................................85
Turbine.............................................................................................................................85
Generators........................................................................................................................85
Transmission Line............................................................................................................85
Power and Energy............................................................................................................86

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Construction Period ..................................................................................................86

Conclusion................................................................................................................................87
References................................................................................................................................88
ANNEX I
Detail Drawings
ANNEX II
Details of Office Work
ANNEX III
Weekly Internship Activities

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LIST OF FIGURES

Figure1: Location Map of Project Site.....................................................................................16

Figure 2: Location Map of Project Site(VIEW B)...................................................................17
Figure 3: Location Map of Project Site....................................................................................17
Figure 4: Balancing Pond of SHEP..........................................................................................24
Figure 5: Weir of Chhupchung Khola......................................................................................26
Figure 6: Desander of Chhupchung Khola...............................................................................27
Figure 7: HRT Inlet Portal.......................................................................................................29
Figure 8: Jackhammer..............................................................................................................33
Figure 9: Charge (Explosive)...................................................................................................33
Figure 10: Packets of sand for stemming.................................................................................34
Figure 11: Rib Installation.......................................................................................................37
Figure 12: Backfilling..............................................................................................................38
Figure 13: Rock Bolts..............................................................................................................39
Figure 16: Spilling dowels for support in Overbreak...............................................................41
Figure 15: Overbreak in tunnel................................................................................................41
Figure 17: Powerhouse SHEP..................................................................................................43
Figure 18: Pressure Grouting...................................................................................................47
Figure 19: Hydraulic excavator at powerhouse site.................................................................48
Figure 20: Concrete Batching Plant.........................................................................................48
Figure 21: Transit Mixer..........................................................................................................49
Figure 22: Sand Washing Plant................................................................................................49
Figure 23: Aggregate Crushing Plant.......................................................................................50
Figure 24: Concrete pump during mass concreting in powerhouse.........................................50
Figure 25: Single Drum Vibratory Roller................................................................................51
Figure 26: Alimak Method.......................................................................................................52
Figure 27: Wheel Loader without backhoe..............................................................................52
Figure 29: Pouring trial mix concrete in cube moulds.............................................................53
Figure 28: Preparation of Trial Mix.........................................................................................53
Figure 30: Placement of concrete in standard cube moulds.....................................................55
Figure 31: Preparation of Cubes for compression test for grout mix.......................................55
Figure 32: Compressive Strength Test.....................................................................................55
Figure 33: Prepataion of Slump...............................................................................................63
Figure 34: Concrete Slump after Removal of Cone.................................................................63
Figure 35: Placement of Appartaus..........................................................................................65
Figure 37: Pouring of sand onto the cylinder while weighing.................................................65
Figure 38: Placement of Cylinder filled with sand..................................................................65
Figure 36: Removal of Soil to be weighed and tested.............................................................65
Figure: Trapezoidal Cross Section...........................................................................................75
Figure: Rectangular Section.....................................................................................................75

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Plan of Sanjen HEP Powerhouse...............................................................................................8

Section of SHEP Powerhouse....................................................................................................8
LIST OF TABLES`
Table 1: Salient Features of Sanjen Hydroelectric Project......................................................20
Table 2: Comparison between SUHEP and SHEP..................................................................22
Table 3: Detail of bends and slope in HRT..............................................................................28
Table 4: Detail of bends and slope in HRT..............................................................................28
Table 5: Design of surge shaft.................................................................................................30
Table 6: Detail of Bends in Penstock Tunnel...........................................................................31
Table 7: Classification of Rock Type based on Q value..........................................................35
Table 8: Rock Support based on Q value for Penstock Tunnel...............................................35
Table 9: Rock Support based on Q value for Penstock Tunnel...............................................36
Table 10: Materials for Grout Mix...........................................................................................40
Table 11: Composition of Grout Mix.......................................................................................40
Table 12: Detail of Bends in Surface Penstock........................................................................42
Table 13: Source of material of bifurcation area in Power House For elevation 1743.40m –
1744.70m..................................................................................................................................44
Table 14: Compressive Strength of 7 days concrete of bifurcation area in Power Housefor
elevation 1744.70m – 1745.50m..............................................................................................44
Table 15: Source of material of bifurcation area in Power House for elevation 1744.70m –
1745.50m..................................................................................................................................44
Table 16: Compressive Strength of 7 days concrete of bifurcation area in Power Housefor
elevation 1744.70m – 1745.50m..............................................................................................44
Table 17: Source of material of bifurcation area in Power House for elevation 1744.70m –
1745.50m..................................................................................................................................45
Table 18: Compressive Strength of 7 days concrete of bifurcation area in Power Housefor
elevation 1744.70m – 1745.50m..............................................................................................45
Table 19: Source of Materials of Trial Mix for PCC in Power House....................................53
Table 20: Composition of Trial Mix for PCC in Power House...............................................54
Table 21: Compressive Strength of 7 days concrete for PCC in Power House.......................54
Table 22: Source of Materials of concrete for Power House Shear Wall(E.L. 1747.50-
1748.00m)................................................................................................................................56
Table 23: Composition of concrete for Power House Shear Wall(E.L. 1747.50-1748.00m). .56
Table 24: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1747.50-1748.00m)..................................................................................................................56
Table 25: Compressive Strength of 28 days concrete for Power House Shear Wall(E.L.
1747.50-1748.00m)..................................................................................................................56
Table 26: Source of Materials of concrete for EDV Power House in SUHEP........................57
Table 27: Composition of concrete for EDV Power House in SUHEP...................................57
Table 28: Compressive Strength of 7 days concrete for EDV Power House in SUHEP.........57
Table 29: Compressive Strength of 28 days concrete for EDV Power House in SUHEP.......57
Table 30: Source of Materials of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+274
to 0+294)m...............................................................................................................................58

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Table 31: Composition of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+274 to
0+294)m...................................................................................................................................58
Table 32: Compressive Strength of 7 days concrete for Fiber Shotcrete in HRT Inlet Tunnel
d/s (0+274 to 0+294)m.............................................................................................................58
Table 33: Compressive Strength of 28 days concrete for Fiber Shotcrete in HRT Inlet Tunnel
d/s (0+274 to 0+294)m.............................................................................................................58
Table 34: Source of Materials for Power House Shear Wall(E.L. 1748.00-1749.00m)..........59
Table 35: Composition of concrete for Power House Shear Wall(E.L. 1748.00-1749.00m). .59
Table 36: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)..................................................................................................................59
Table 37: Compressive Strength of28 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)..................................................................................................................59
Table 38: Source of Materials for Power House Shear Wall(E.L. 1748.00-1749.00m)..........60
Table 39: Composition of concrete for Power House Shear Wall(E.L. 1748.00-1749.00m). .60
Table 40: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)..................................................................................................................60
Table 41: Compressive Strength of 28 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)..................................................................................................................60
Table 42: Source of Materials of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409
to 0+417)m...............................................................................................................................61
Table 43: Composition of Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409 to 0+417)m........61
Table 44: Compressive Strength of 7 days Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409 to
0+417)m...................................................................................................................................61
Table 45: Source of Materials of concrete for Adit 1 Backfill –C12/15 (0+595.0m)..............62
Table 46: Composition of concrete for Adit 1 Backfill –C12/15 (0+595.0m).........................62
Table 47: Compressive Strength of 7 concrete for Adit 1 Backfill –C12/15 (0+595.0m).......62
Table 48: Result of Slump Tests..............................................................................................64
Table 49: Result of Field Density Test of compacted soil of powerhouse from EL 1746 to
1747m.......................................................................................................................................66
Table 50: Summary of Result of Field Density Test of compacted soil of powerhouse from
EL 1746 to 1747m....................................................................................................................66
Table 51: Result of Field Density Test of compacted soil of powerhouse from 1747 to
1749.80m..................................................................................................................................67
Table 52: Summary of Result of Field Density Test of compacted soil of powerhouse from
EL 1747 to 1749.80m...............................................................................................................67
Table 53: Summary of the menu are provided.........................................................................73
Table 54: Value of Standard Normal Variant for Corresponding Return Period....................77

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CHAPTER 1

INTRODUCTION

1.1. Overview of Internship

As per the requirement of course of Civil Engineering Program in School of Engineering,
Kathmandu University there is a provision of internship in different reputed organizations of
Nepal specializing in hydropower development. In total the course for Civil Engineering has
been designed by the Department of Civil Engineering for seven semesters comprising of in
house 141 credit hours. One semester of the eight has been provided with 3 credit hours of
off-campus internship at a Host Organization and 9 credit hours of final major project. This
internship has been facilitated in the eighth semester.

After the completion of their in-campus course works, the final year students must work at
Host Organization related to hydropower development as interns. The internship will be for a
maximum of 6 working weeks with 8 hours per day of work load. This allows the students
the opportunity to acquire corporate knowledge, hands on technical skills, soft-skills and
potential placement. At the same time, the Host Organization benefits in terms of lead-time
and human resource identification.

Thus under such provision we have pursued our internship at Sanjen Hydroelectric Project in
Chilime VDC, Rasuwa under the supervision of Host Organization;Chilime Engineering and
Services Company Ltd. (ChesCo).

1.2. Objectives and Scopes

i. Objectives
a. To familiarize and get a sense of day-to-day operations in a Hydroelectric Project
in the site.
b. To familiarize with engineering duties and responsibilities while still being aware
of ethical practices and norms.
c. To develop adeptness to function in the engineering and managerial settings based
upon the skills and knowledge acquired during the in-campus lectures.
d. To get acquainted with the construction of the overall Hydroelectric Project
specifically the methods utilized for the construction and problems encountered
during the construction process.
e. To acquaint the interns on how to educate and motivate clients about the
activities of Host Organization.

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ii. Scopes of work

a. To be involved in the day-to-day activities in the Hydroelectric Project as
instructed by the Supervisor assigned by the Host Organization.
b. Document the day-to-day activities and report back to supervisor assigned by the
Department in a weekly log-sheet format.
c. Utilize the theoretical knowledge gained in-campus and applying it to solve
problems faced by the Host Organizations under the instructions of the supervisor
assigned.
d. Engage in discussions with supervisor and superiors in order to complete
objectives placed forward.
e. Accomplish tasks, engineering or managerial, provided by the supervisor
complying with engineering ethics and norms.
f. To demonstrate that the intern has the attitude and aptitude to grasp all necessary
fundamentals to become a fully well-groomed professional.

1.3. Project Background

Sanjen (Upper) Hydroelectric Project (SUHEP) is located on the Sanjen River in Rasuwa
District, Bagmati Zone of the Central Development Region and the River is one of the
tributaries of the Bhotekoshi River of the Gandaki basin. A feasibility study into the project
reported in 2011, and the detailed designs and Bid documents have been prepared in early
2012.

Topographic surveys and field investigation drilling works have been carried out. The
Environmental Impact Assessment (EIA) report concluded that the Project is an
environmentally friendly project with few adverse impacts compared to most other
comparable run-of-river hydropower projects, and has been approved by the Government of
Nepal.

SUHEP is a run-of-river hydropower development with a live storage volume in the peaking
reservoir sufficient for 2 hours daily peaking operation. Compared with other run-of-river
projects investigated in Nepal, SUHEP is one of the attractive projects due to its low specific
investment costs and its limited environmental impacts. The intake for SUHEP is located at
Tiloche, some 165 km north of Kathmandu and 6 km south of the border with People’s
Republic of China, at a distance of 44 km north from the district headquarters, Dhunche. The
project will exploit a gross head of 161.3 m on the Sanjen River over a reach of about 2 km
along the river to the tailrace outlet about 150 m upstream from the confluence of the
ChhupchhungKhola with the Sanjen River. The surface powerhouse is located near Simbu
village, and three horizontal-axis Francis turbine/generating units are to be installed, each of
rated capacity 5.1 MW.

Sanjen Hydroelectric Project (SHEP) is located on the Sanjen River in Rasuwa District,
Bagmati Zone of the Central Development Region. SHEP is a cascade run-of-river
hydropower development that utilizes the water from the tailrace of SUHEP powerhouse.

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Additionally, SHEP utilizes 0.5 m3/s water from ChhupchhungKhola. SHEP is one of the
attractive projects due to its low specific investment costs and its limited environmental
impacts. SHEP has major structures viz. forebay, headrace tunnel, underground surge tank,
inclined and horizontal pressure shaft, powerhouse and tail race structures.Generation
License for these projects was obtained from Ministry of Energy on August 2012 and
November 2011 respectively valid for 35 years including the period of construction on Build
Own Operate Transfer (BOOT) basis.

Geographically, the project area lies between longitudes from 85 0 16' 30' E to 850 18’ 15" E
and latitudes from 280 11' 00" N to 280 13' 00" N. Site is considered as remote area. The
project is accessible via Kathmandu-Trisuli road (72 km), Trisuli-Somdang Highway
(PasangLhamu Highway 72 km) and 6 km long access road up to existing headworks of
Chilime Hydroelectric Project. The access road to the power house and headwork is
constructed by the company.

The Site is situated in high altitude and sometimes snowfall occurs in winter. Concreting
during this period might be required to do in frosty condition. Construction works at forebay
will have to be carried out in high altitudes above 2100 m above mean sea level and
sometimes snowfall occurs in winter. In this elevation works may have to be executed in cold
condition and Concreting during this period might be required to do in frosty condition in the
winter season. Construction at powerhouse area is expected to be slightly more comfortable
since this area lies about 400 m lower from the level of forebay area.

Figure1: Location Map of Project Site

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Figure 2: Location Map of Project Site(VIEW B)

Figure 3: Location Map of Project Site

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1.4. Project Features

Sanjen (Upper) Hydroelectric Project (SUHEP) is located on the SanjenKhola, a tributary
of the Trishuli River, at Chilime VDC in Rasuwa district of the Central Development Region
of Nepal. Sanjen (Upper) Hydroelectric Project (SUHEP) is located at 150 km road head
distance towards north-west of Kathmandu. Geographically the project area lies between
longitudes from 85016'30" E to 85018'15" and latitudes from 28013'00"N to 28014'25"N.The
headworks site of Sanjen (Upper) Hydroelectric Project is located at Tiloche about 2 km
upstream from the confluence of the SanjenKhola and ChhupchungKhola whereas the
Powerhouse is located near Simbhu Village just upstream of confluence of SanjenKhola and
ChhupchungKhola. At the installed capacity of 14.8 MW, it is estimated that the average
annual energy production will be 85.87 GWh.The project will exploit a gross head of 161.3 m
on the Sanjen River over a reach of about 2 km along the river to the tailrace outlet about 150
m upstream from the confluence of the Chhupchhung Khola with the Sanjen River. The
surface powerhouse is located near Simbu village, and three horizontal-axis Francis
turbine/generating units are to be installed, each of rated capacity 5.1 MW.

Sanjen Hydroelectric Project(SHEP) is located on the Sanjen River in Rasuwa District,

Bagmati Zone of the Central Development Region and the river is one of the tributaries of
Bhotekoshi River of Gandaki Basin. The project area lies between longitudes from
850 16' 30' E to 850 18’ 15" E and latitudes from 280 11' 00" N to 280 13’ 00" N.

Sanjen Hydroelectric Project receives tailwaters from SUHEP power house and additional 0.5
m3/s discharge from Chhupchung Khola at Simbu and its powerhouse is located at Chilime
Village adjacent to Headworks of existing Chilime Power Plant.

Project utilizes design flow of 11.57 m3/s at 40 percentile flow exceedance of long term
available river discharge and 442 m gross head to produce 42.5 MW power and 251.94 GWh
gross energy per annum. SHEP comprises a 3629m long headrace tunnel, a 1018m long
pressure shaft. Three vertical axes Pelton turbines of 15MW capacity each will be installed in
a surface powerhouse at Chilime Village in ChilimeVDC.Generation voltage of 11kV is
stepped up at the switchyard by 11/132 kV transformer and 1.1 km 132 kV transmission line
connected at Chilime hub will be constructed for power evacuation.

Hydrology

Sanjen (Upper) Hydroelectric Project is basically a run-off-river scheme with the provision
of daily peaking pondage for 1.2 hours. The headworks site of Sanjen (Upper) Hydroelectric
Project is located at Tiloche about 2 km upstream from the confluence of the SanjenKhola
and ChhupchungKhola. This project utilizes water from SanjenKhola. The main attractive
feature of this project is the peaking pondage. The design discharge is 11.07 m 3/s which is
equivalent to 40% exceedence flow.

Sanjen Hydroelectric Project (SHEP) is a cascade run-of-river scheme which diverts the
tail water coming from the powerhouse of Sanjen (Upper) Hydroelectric Project and the
additional water (0.50m3/sec) from the ChhupchhungKhola. The major headworks structure
of the SHEP will be a forebay cum intake structure. Water discharged from tailrace of

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SUHEP powerhouse and the water from the ChhupchhungKhola through feeder canal system
will be collected in this forebay. There will be a simple intake structure, desander and a
feeder canal to feed water from ChhupchhungKhola which is designed to convey 0.5m 3/s of
water from the intake and discharge to the forebay of the interconnection system. Adding this
flow, the design discharge adopted for SHEP is 11.57 m 3/s. The forebay is provided with side
channel spillway.

Geology:

The project area is situated in the Higher Himalaya and the Lesser Himalaya, Central Nepal
separated by the Main Central Thrust (MCT). Chhupchhung weir lies in recent alluvial
deposits consisting of predominately coarse gravel toboulder derived from gneiss, schist,
quartzite and slate in sand matrix with large boulders ofaugen gneiss. Forebay/Intake of
SHEP is in a gently sloping terrain consisting of about 25-30m thick deposits with angular
gravel to boulder sized rock fragments of powerhouse lies on a flat alluvium terrace
consisting of a thick accumulation of alluvial deposits having sharp-textured, angular to sub-
rounded, coarse-grained soil with gravels.

Contracting Parties:
The Contract for the Construction of the main Civil Work is the major Contract under the
Sanjen Hydroelectric Project to generate 42.5 MW power (electricity). Since the taking over
of the site, the Contractor SEW Infrastructure Limited, India and Tundi Construction Co. Pvt.
Ltd., Nepal J/V (SEW-TUNDI JV), has been doing its best; in mobilizing resources and
executing the works.
Client
SanjenJalavidyut Company Limited (SJCL)
Ground and First Floor, Kapan Marg
Maharajgunj, Chakrapath, Kathmandu, Nepal
Consultant
Chilime Engineering Services Company Ltd.
Second and Third Floor, Kapan Marg
Maharajgunj, Chakrapath, Kathmandu, Nepal
Head Office: Maharajgunj, Chakrapath, Kathmandu, Nepal
Lot 2: Contractor
SEW (India) – Tundi (Nepal) Joint Venture
SEW Infrastructure Limited
6-3-871, Snehalata, Greenlands Road, Begumet,
HYDERABAD- 500 016, Andhra Pradesh, India.
TundiConstrucion Pvt. Ltd.
Shanti Basti, Sanepa , Ring Road,
Municipality: Lalitpur, Ward No.:03, Lalitpur, Nepal

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Lot 3: Contractor
Dongfang Electric International Corporation (DEC)
18 Xixin Avenue, High-tech Zone west Park,
Chengdu, 611731, Sichuan, P.R. China
Lot 4: Contractor
Nepal Hydro & Electric Limited (NHE)
P.O. Box: -1, Butwal, Nepal

1.5. Salient Features

1.5.1. Salient Features of Sanjen Hydroelectric Project

Table 1: Salient Features of Sanjen Hydroelectric Project

Location Chilime V.D.C. of Rasuwa district.

Longitude from 850 16' 30' E to 850
18' 15" E
Latitude from 28013'00"N to 28014'25"N
Type of Project Cascade Run-of-River
Installed Capacity 42.9 MW
Hydrology
Catchment Area 180 km2 at SUHEP Intake
24 km2 at Chhupchung Intake
Design Flow(Q40) 11.57 m3/s
Geology Rock Type: Medium grade metamorphosed
schist and quartzite
Head Gross: 442.00 m
Net: 432.80 m
Headworks
Intake Basin (Forebay) 8.06 m (l) × 21 m (b) × 11 m (d)
Intake Type Off take from Tail water of SUHEP
Headrace Tunnel
Length 3629 m
Size of excavation 3.50 m (w) × 3.75 m (h): D-shaped
Surge Tank
Type Restricted Orifice Type
Size 55.00 m (h), 5.50 m (dia)
Size of orifice 1.70 m (dia)
Penstock Shaft 1018 m(l), 2.5 m (dia)
Powerhouse Surface, size: 55.75 m (l) × 12.0 m (b) ×
29.7 m (h)
Tailrace 123.8 m (l) × 2.7 m (b) × 2.7 m (h)
Turbines Pelton, Vertical Axis; Capacity: 3 Nos,,
15MW
Generators 3Phase Synchronous AC; 3Nos., 17.2
MVA each

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Energy Generation
Annual Energy Generation
Total 253.447 GWh
Dry Months Energy 35.116 GWh
Wet Months Energy 218.331 GWh
Annual Contract Energy
Total 243.31 GWh
Dry Months Energy 33.71 GWh
Wet Months Energy 209.60 GWh
Transmission Line Length 1km, 132KV
Access Road 7Km
Project Cost
Total cost before financing NRs. 5,024,289,001.
Total financial cost NRs. 5,914,661,650.
Financial Indicators
As independent
IRR 15.36 %
ROE 18.47%
B/C 1.27
NPV (MNPR) 1090.848
As cascade system
IRR 14.087 %
RoE 16.589 %
B/C Ratio 1.14
NPV (MNPR) 841.373

Sanjen Upper
Sanjen Hydroelectric
Descriptions Hydroelectric project
project(SHEP)
(SUHEP)
Cascade Peaking Run-of-
Type of project Peaking Run-of-River
River
Design Flow 11.07m3 11.57m3
Gross Head: 161.3 m 442m
Off-take from tail-water of
Overflow weir type with
Headworks: SHUEP and chhupchung
undersluice and side intake
feeder
Surface Pondage
Desander Type and Size:
60m(l)x8.5m(b)x7.10m(h) 80m(l)x30m(b)x8m(h)
1377m(l) 3630m(l)
Headrace Tunnel length
and size:
3.5m(b)x3.75m(h) 3.5m(b)x3.75m(h)
480m 1020m
Penstok Length and size
1.1m to 2.5m in diameter 1.1m to 2.5m in diameter
Surface Semi surface
Power House Type and
Size:
45.8m(l)x14m(b)x23m(h) 57.5m(l)x30m(b)x15m(h)
Turbine type, Francis Pelton
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Orientation, Horizontal axis Vertical axis

Number & 3Nos 3Nos
Unit capacity: 5.1MW each 15MW each
Generator unit Capacity 3 Phase synchronous 3 Phase synchronous
and AC,5.85 MVA AC,16.4 MVA
Numbers 3Nos 3Nos
Installed Capacity: 14.8 MW 42.5 MW
Annual Salable Energy 82.439 GWh 241.865GWh
Dry Energy 10.583 GWh 34.28 GWh
Wet Energy 71.856 GWh 207.58 GWh
Transmission line length
5 km/132 KV 2.0 km/132 KV
and voltage

1.5.1 Comparison between SUHEP and SHEP

Table 2: Comparison between SUHEP and SHEP

CHAPTER 2

COMPONENTS OF THE PROJECT

2.1. Project Layout

Sanjen Hydroelectric Project (SHEP) is a cascade development project with SUHEP and for
additional 0.5m3/s discharge from the headwork at Simbu. Headwork lies at 150 m upstream
from the confluence of ChhupchhungKhola with Sanjen River. This scheme diverts water of
Sanjen River through 8 km long headrace tunnel and 3500 mm diameter, 1020m m long
penstock pipe (inclined as well as horizontal) to the powerhouse located near Chilime village
in on the right bank of Sanjen River.
The general layout of SHEP consists of a 37m long protection wall and 11m wide weir with
20m long Launching apron and 1.0 m high diversion weir across Chhupchung Khola, a side
intake on the left bank, a 10.75 m long gravel trap with a side spillway, a single chambered
Desander of length 32.0, Connection pipe of 32.67m long, Balancing pond of 80.0 x 30.0
(LxW), an approximately 3.6 km long low pressure headrace tunnel, an underground surge
shaft, 1020 m long penstock and surface powerhouse at right side of the Headwork of
Chilime Hydropower canal. The powerhouse will accommodate three units of Vertical axis
Pelton turbines having a total installed capacity of 42.5 MW. The water from the tailrace will
feed the downstream 22.0 MW Chilime Hydroelectric Project as a cascade development.
General arrangement
The general arrangement of the components of SHEP consists of following major structures
are:
• Non-gated overflow diversion weir
- Diversion Weir in Chhupchung
- Intake structures with one opening
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- Spillway and flushing canal

• Desander
• Connection Pipe from SUHEP to Balancing Pond
• Balancing pond
• Siphon
• Inlet portal of HRT
• Headrace Tunnel (Soft Ground Tunneling)
• Headrace Tunnel
• Adit 1 (Brapche)
• Adit 3
• Access Tunnel to valve Chamber
• Surge Shaft
• Aeration Tunnel
• Upper Inclined Penstock
• Intermediate Penstock Tunnel
• Penstock Adit
• Lower Inclined Penstock
• Horizontal Penstock/Outlet portal
• Powerhouse arrangement
- Powerhouse
- Service Bay
- Generation Hall
- Control system
• Tailrace
• Switch Yard

2.2 Headworks

2.2.1 Tailrace Canal and Forebay with side channel spillway

The tailrace from each unit discharges water to the forebay located near the suspension bridge
at the right bank of Sanjen River, upstream from the confluence of Chhupchung Khola with
Sanjen River. Each tailrace will be equipped with tailrace outlet gates, which will be used
during maintenance of one unit. Size of the forebay will be 68.06 m long, 21m wide and 11m
deep. Full supply level of the forebay will be 2187.00m
Intake of the lower scheme of 42.9 MW capacity plant is arranged in the forebay with an
invert level of 2177.00. The intake structure is equipped with a gate sized 2.50 m X 2.50 m
and a safety rack. The intake is designed to pass the design discharge of 11.57 m 3/s (11.07
m3/sec from tailrace of the upper scheme and 0.5 m3/sec from Chhupchung Khola) to the
low-pressure tunnel through 75m long inverted steel pipe across Chhupchung Khola.

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Figure 4: Balancing Pond of SHEP

2.2.2 Feeder Canal from Chhupchung Khola

Due to the high head available for power generation in SHEP project, a small discharge of
Chhupchung Khola will be valuable. Hence simple intake structure, desander and 220.35 m
long feeder canal are proposed to feeds water from Chhupchung Khola. It is designed to
convey 0.5m3/s of water from the intake and discharges it to the forebay of the
interconnection system. Adding this flow, the design discharge adopted for SHEP is 11.57
m3/s.

2.2.3 Feeder Canal from Chhupchung Khola

Due to the high head available for power generation in SHEP project, a small discharge of
ChhupchungKhola will be valuable. Hence simple intake structure, desander and 220.35 m
long feeder canal are proposed to feeds water from Chhupchung Khola. It is designed to
convey 0.5m3/s of water from the intake and discharges it to the forebay of the
interconnection system. Adding this flow, the design discharge adopted for SHEP is 11.57
m3/s.

2.2.4 Weir of Chhupchung Khola

The weir is the simple diversion type weir with abrasion resistant concrete at the surface. The
upstream of the weir consists of Gabion Protection wall at 12.53m upstream from a weir which
extends up to 9.35m further from that point. The size of the gabion protection wall provided is 2m
in width and 10.82m in length. The height varies from 3m at farthest end and 4.5m at the nearest
end. After the gabion wall, flood protection wall is provided on both sides of the section. The
boulder riprap of width 4.24m is provided to avoid the river bed surface from erosion and
washout. For boulder riprap, the thickness of 0.8m and 1m boulder are provided. The surface
level of boulder riprap is 2187.20 m amsl. After the riprap, upstream apron is provided of length
8.29m. The surface level of the upstream apron is 2187.20 mamsl. The intake structure is
0
provided 65 about the center line of river flow. The intake structure is at 3.2m distance from the
weir, measured between the centerline of the two structures. The length of the weir is 11m while

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the width of the weir is 12m. The cutoff wall is provided after the boulder riprap and at the start
of the upstream apron. The bottom level of the upstream cutoff wall is 2184.20mamsl. The u/s
cutoff wall is of the trapezoidal section with 0.5m width at the bottom and 1m width at the top.
For concreting of the weir, fore apron and back apron 0.1m thick structural concrete of grade C
8/10: X0 and 0.4m thick abrasion concrete C25/30 is used. The upstream apron is of length
6.51m. In rear apron weep holes are provided to relieve the upthrust given by the underground
water. The level of the downstream apron is 2184.00 amsl and the length is 14m. At the end of
the spillway of the weir, the cutoff wall is provided of thickness 0.50m at the bottom and 1.1m
thick at the top of the cut off wall. At the end of the rear apron, the small cutoff wall is also
provided 0.5m thick at the bottom and 1m thick at the top. For the downstream apron, first layer
filter fabric geotextile is provided and then lean concrete of 0.1m thick of grade C8/10 provided
then 0.4m concrete of grade C25/30 is provided on top of which abrasion resistant concrete of
0.1m thickness

Figure 5: Weir of Chhupchung Khola

2.2.5 Intake

The type of intake in Chupchung Khola is Orifice type intake. The sill level of the intake is
2187.50amsl so that 0.3m height is as the dead zone for sediment deposition in weir. The
0
intake trash rack is provided at an angle of 80 with the size of 1.5m width x 1.1m height.
The orifice opening is 0.7m. At the start of the orifice opening, intake gate of size 1.5 m
width and 0.7m height is provided. The intake gate is regulated by hoisting equipment. The
cutoff wall provided at the start of the intake with 0.5m width at the bottom and 1m width at
the top. The intake structure is of length 5.86m. The top level of the intake structure is at
2191.00m amsl elevation. The concrete grade of the intake structure is C25/30.

2.2.6 Gravel Trap

The gravel trap starts after the intake structure with the inlet transit of length 1.8m and total
section length of 13.06m with the slope of 1: 41.67. The normal water level at the gravel trap

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is 2187.98mamsl. The concrete thickness provided is 0.6m. The flushing of the gravel trap is
done by a square culvert of dimension 0.7m. At the inlet of the culvert, gravel flushing gate
is provided which is regulated by hoisting equipment. The structural concrete thickness of
culvert is 0.3m all-around of concrete grade C25/30.

2.2.7 Spillway

After the gravel flushing along the feeder, canal spillway is provided of length 4m and
height of 1m. The spillway provided is broad chested spillway. Weep holes of 100mm
diameter are provided at the walls of the spillway. The total length of the spillway is
13.06m.

2.2.8 Desander

After the feeder canal, desander starts. Desander is of one chamber with hoper type. The
inlet transit length of the desander is 6m while the outlet transit length is 4.9m. The normal
water level at desander is 2187.88mamsl. At inlet transit, the expansion of 1m width of the
feeder canal to 4m width of desander takes place. The slope of desander is 1:50. The wall of
the desander varies from 0.3m at the top and increases upto 0.4m at the bottom section. The
height of the desander including free board is 2.55m. The hooper end at bottom is of width
0.8m and height varies from 0.2 at the start of the slope of the desander and increases to
0.95m. Two sub surface drains are provided along the length of the desander with opening
200mm diameter.

The flushing of desander is provided along with the side drain which flushes out the
sediment collected to the riprap area downstream of the weir. The slope of the desander
flushing canal is 1:31.59. The flushing of the desander is controlled by the regulating gate
kept at the start of the desander flushing canal regulated by the hoisting equipment. The size
of the desander flushing box culvert is 1.5m in height and 0.8m in width.

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Figure 6: Desander of Chhupchung Khola

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2.3 Head Race

2.3.1 Inlet Portal of Headrace Tunnel

The inlet portal of headrace tunnel present in Simbubegins after a steel syphon pipe of 110m
length and 2.40m diameter from head pond outlet block. The inlet portal is 34.50 m long
which is an inverted –D in shape, with spring level height of 2m and crown height of 1.90 m.
The steel siphon pipe of 12mm thickness continues into this section until the start of the head
race tunnel where the siphon pipe diverges in to the tunnel cross-section. Here the portal face
and cut slopes have been secured by wire mesh shotcrete of 1.5m thickness in two layers.
Along the inlet of the headrace concrete of C25/30 is to be backfilled after placement of the
steel siphon pipe until the start of the headrace tunnel. 50mm shotcrete of C28/35 has been
provided for support, invert of 40cm of same specification and weep holes have been
installed at a spacing of 2m provided via 40mm PVC perforated pipe to release pore water
pressure.

2.3.2 Head Race Tunnel

The length of headrace tunnel in this project is 3628.46 m which begins after 34.50m from
the inlet portal, this was due to presence of soft and loose soil, thus installation of steel siphon
pipe has been proposed till the start of head race tunnel which is soft ground tunneling for
HRT. HRT ends at the surge shaft accessible via adit 3. HRT is inverted –D in shape, with
spring level height of 2m and crown height of 1.75 m and width of 3.75m .The HRT consists
of 4 bends of varying radius of 50m for the 1 st bend and 100m for the remaining bends. Also
the HRT has varying slopes, ranging from 1:1469.46 to 1:80.19.

The details of the bends and varying slope in the HRT are presented in the tables below.
Table 3: Detail of bends and slope in HRT

Bend Start of Bend in End of Bend in Radius of Bend(m)

chainage (m) Chainage (m)
Bend 1 0+075.034 0+096.836 50
Bend 2 1+711.012 1+724.127 100
Bend 3 3+0.84.383 3+159.170 100
Bend4:4 Detail of bends and
Table 3+454.081
slope in HRT 3+511.458 100
Slope Start of Slope End of Slope
1:1000 0+000.00 0+500.00
1:132.17 0+500.00 1+558.05
1:1469.46 1+558.05 1+972.090
1:80.19 1+972.090 3+567.090

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Figure 7: HRT Inlet Portal

Lining Type Finished Diameter (m) Length (m)

Shotcrete lined 3.2 2178

Concrete lined 2.8 1451

About 60% of the length of the headrace tunnel is estimated to be shotcrete lined of 10 to 15
cm thickness and 40% of length is estimated to be concrete lined at this stage

For the purpose of construction of HRT two aditsare present, namely Adit 1 in Brapchhe and
Adit 3 which diverges into the penstock tunnel.

(Detail Drawings have been provided in ANNEX I)

2.3.3 Rock Trap

A rock trap is a depression present in the tunnel used mainly in the downstream to trap rocks
and rock fragments from entering the penstock and vis-à-vis the turbine. In the case of SHEP
a rock trap 45m in length with four compartments, outer two being 11.10 m in length and
inner ones being 10.95 m and depth of 1.6m. The invert lining used for the rock trap is
300mm thick concrete of C28/35 and shotcrete of 50mm has been provided for support of
same specification and 300 mm thick concrete of C20/25 grade has been provided.

(Detail Drawings have been provided in ANNEX I)

2.3.4 Surge Shaft

Surge tank at transition section between headrace and penstock has been proposed for various
reasons and are:

• To relief the wave developed due to the water hammer at the time of sudden load rejection
of turbine through open atmospheric zone near the plant.

• To protect the penstock from detrimental effect of water hammer pressure developed in the
pipe due to fast closure of spear valves of the turbine.

• To improve the regulation of flow during variation of flow to the plant.

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• To fulfill the initial demand during staring up of the turbine.

The surge shaft is of restricted orifice type at the bottom to supply the water requirements or
to store the excess water caused due to the variations in the power discharge resulting from
the variations in the power generations.

The surge shaft is present in here after the rock trap present at a chainage of 3+635.16 where
the start has been taken from the start of head race tunnel. Here the excavation diameter is
6.60m and nominal diameter for the surge tank is 5.50m whereas the opening for the surge
tank is 1.24m in diameter which increases to 2.64, reaches the nominal diameter 5.50m and
finally reaching 5.80m in diameter as thickness of concrete decreases. The surge shaft
consists of a dome of radius 3.30m which is connected to an aeration tunnel of diameter 2.70
lined by 50mm shotcrete at the crown and 20cm concrete of C20/25 grade as invert lining.
The aeration tunnel is present at downward slope of 1:27 with a bend of 20 m radius at
0+013.19 chainage from aeration tunnel portal ending at 0+028.76m. The aeration tunnel
portal consists of 35cm concrete of C20/25 at the top and 40 cm of the same specification
concrete on the bottom. In totality the height of the surge shaft is 55m.

For rock support grouted rock bolts of 200mm diameter and 3m long have been used. These
have been bolted at a spacing of 1.5m and placed with 100mm shotcrete of grade C28/35.

Table 5: Design of surge shaft

(Detail Drawings have been provided in ANNEX I)

Description Values(amsl)
Minimum Downsurge Level 2164.42
Normal Water Level 2183.43
Static Water Level 2187.00
Maximum Upsurge Level 2198.29

2.3.5 Valve Chamber

A valve chamber as defined by U.S. Department of Interior isa chamber in which a guard
gate in a pressurized outlet works or both the guard and regulating gates in a free-flow outlet
works are located is called a valve chamber. It is also known as a room from which a gate or
valve can be operated, or sometimes in which the gate is located. It is the concrete portion of
an outlet works containing gates between upstream and downstream conduits and/or tunnels.

In SHEP the size of main valve chamber is larger than that of tunnel size. The entrance of
valve chamber is of dimension 4.2m(in width)*7.25m(in height) and the main valve chamber
is of dimension 5.28m (in width)* 8m(in height).

A butterfly valve is to be placed at a chainage of 3+662.01m from the start of headrace

tunnel. A Butterfly valve is a quarter-turn rotary motion valve that is used to stop, regulate,
and start the flow. Butterfly valves are a quick open type.

The main valve chamber has been placed with and inverts lining of 20cm thickness of
concrete of grade C20/25. For support of the valve camber 10cm fibre shotcrete of C28/35
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has been placed and has been reinforced with rock bolt of 3m length of 20m diameter at a
spacing of 1.5m.

(Detail Drawings have been provided in ANNEX I)

2.3.6 Penstock Tunnel

A penstock is an enclosed pipe that delivers water to hydro turbines. A penstock is a steel or
reinforced concrete conduit to resist high pressure in the water conveyance system and may
take off directly from behind a dam, from a forebay, or from the surge tank end of a head race
tunnel.

The penstock will be inclined shaft at two places at 50-degree angle with almost equal length
and middle part connecting with horizontal penstock. The lower part of penstock including
manifold is proposed to be horizontal, some part of it will be constructed as cut and cover
type. The total length of the penstock including manifolds will be 1018 m.

The Penstock Tunnel starts at the chainage of 3+635.16m to the chainage of 4+405.15m
chainage taken from the start of HRT with the length of 1020m. It consists 2 inclined
sections. The inlet diameter of the penstock tunnel is 2.5m varying to 2.3m and that of outlet
is 2.2m. Excavation is Circular in inclined sections and D shaped in the horizontal sections.
The Tunnel is completely backfilled with concrete in order to support the Penstock pipe with
concrete of C12/15 grade. It is also supported by steel lining and shotcrete of 5cm thickness
of grade C28/35 with permanent grouted rock bolts of 20mm diameter which is 1.5m long a
spacing of 1.5m. The excavation diameter is 3.2m in circular sections and for the inverted D
sections with 3.2m height and spring line of 1.60m and crown height of 1.60m.
Table 6: Detail of Bends in Penstock Tunnel
Bend Start of Bend in End of Bend in Radius of Bend(m)
chainage (m) Chainage (m)
Bend 1 3+674.95 3+684.53 12.50
Bend 2 3+845.28 3+854.86 12.50
Bend 3 3+951.78 3+961.35 12.50
Bend 4 4+107.84 4+117.32 12.50

(Detail Drawings have been provided in ANNEX I)

2.3.7 Adit Tunnel

Adit tunnel is a horizontal or near-horizontal passage driven from the Earth’s surface into the
side of a ridge or mountain for the purpose of efficient working, ventilating and inspection of
the tunnel. The size and cross section of an adit depend upon its use, with a horseshoe shape
especially common.

There are two Adit tunnels in SHEP, namely Adit 1 and Adit 3.

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2.3.7.1 Adit 1
The length of Adit 1 is 129.89m with 1 bend of Radius 30m. The width of adit tunnel is 3.5m
and height is 3.75m. The rock support of grouted rock bolts of 3m long and 20mm diameter
in 1.5m spacing and 5 to 10 cm shotcrete. The adit 1 is to be plugged after the completion of
the HRT by C20/25 grade concrete. The steel reinforcement of 20mm diameter with 200mm
spacing is used along the length and in the entrance its 25mm diameter with 200mm spacing.

2.3.7.2 Adit 2
The length of Adit 3 is 179.81m with 1 bend of Radius 50m. It provides an access to the
valve chamber. The width of adit tunnel is 4.2m and the height is 3.75m with spring line
height of 1.65 ma and crown height of 2.10m. The rock support of grouted rock bolts of 3m
long and 20mm diameter in 1.5m spacing and 5 to 10 cm shotcrete.

2.4 Tunnel and it’s construction

Tunnel is an underground structure, usually made for either water conveyance or for
transportation. It is one of the most favored techniques for both water conveyance and
transportation in the modern day world.
In this project it has been used for water conveyance system from outlet of balancing pond to
start of surface penstock, where later water is conveyed by surface penstock to the
powerhouse.

SHEP consists a tunnel for siphon pipe from balancing pond to HRT inlet of 110m, HRT of
3628.46m and a penstock tunnel of 770m in length.

For the process of rock excavation Drill and Blast Method has been for the tunnels and for
inclined excavation in penstock tunnel Alimak has been used.

Drill and blast tunneling is a method of excavation involving the controlled use of explosives
to break rock.

The typical cycle of excavation by blasting is performed in the following steps:

1. Drilling blast holes

2. Loading them with explosives(Charging)
3. Stemming the blast holes
4. Detonating the blast
5. Ventilation to remove blast fumes.
6. Removal of the blasted rock (mucking)
7. Scaling crown and walls to remove loosened pieces of rock
8. Geological Mapping
9. Installation of support

2.4.1 Drilling
For the purpose of drilling in SHEP jackhammers have been used. They are air driven. The
drill holes are drilled using sufficient circulation of water in order to remove sediments and
also dust from the drill site which is known as hole flushing thus, this type of drilling is

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known as Wet Drilling. The drill bit for drilling is 38mm in diameter. Holes 7 ft deep are drill
on to which explosives are to be loaded. The drill pattern used is wedge pattern.

Figure 8: Jackhammer
2.4.2 Charging
It is the process of insertion of the explosives into the drill holes. Here emulsion type
explosives were being used as explosives. Explosives of 32 mm diameter and of 200 gm were
being used. Explosive named SUPERPOWER-90 was being used in the case of SHEP. The
quantity of explosive used is determined by the type of rock increasing with the hardness of
the rock.

Figure 9: Charge (Explosive)

2.4.3 Stemming
It is the process of sealing the drill hole and retaining the explosive gases within it. For this
purpose packets filled with sand are prepared in the site, which is inserted in to the drill hole
after charge has been placed.

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Figure 10: Packets of sand for stemming

2.4.4 Detonation
Detonation is the process of exploding the charges via detonators. Detonators are attached to
the explosive and the individual explosive are connected to one another. The holes are blasted
in a proper sequence, from the center to outward, one after the other. The blast sequence is
completed in several seconds. In the case of SHEP, it took about 5mili seconds for the charge
to explode after denotation. After detonation the expanding gas enters into the cracks and
bursts open the ground. The gas pressure does the majority of the work during detonation.

2.4.5 Ventilation
In tunnel excavation, a ventilation system is required to provide an acceptable working
environment for the people of the tunnel. The environment is affected by the concentration of
impurities in the tunnel air. The impurities are mostly created by blasting and traffic in the
tunnel.Ventilation is done by using so-called air-ducting systems, long steel or plastic pipes,
which are attached to the roof of the tunnel and blow fresh air onto the working face. This
gives rise to localized excess pressure and the bad air is pushed towards the tunnel exit. In
case of SHEP, blowing ventilation has been used to dilute the explosion gas so that toxic gas
concentration is of the acceptable value.

2.4.6 Mucking
Mucking can be defined as cleaning of the excavated materials as well as its transportation
out of the tunnel. For this purpose the loaders are used on to which the material is loaded and
transferred out of the tunnel. In case of SHEP, the muck from Audit 1 was transported to PH
area for the purpose of filling.

2.4.7 Scaling
Scaling is defined as the process of scraping off the loose or jointed rock from the surface of
the walls of tunnel to prevent the injury from the falling rock pieces while the working on
tunnel. Scaling is performed prior to applying the rock reinforcement and support. Normal
scaling requires the prying without loosening adjoining rock, substantially locked in place,
and/or the use of the air-water flushing. Scaling is first performed by mechanical equipment
then is done by control manual control scaling is performed.

2.4.8 Geological Mapping

After mucking and scaling have been done, the excavated face is accessible and geological
mapping is carried out of the face to find the actual condition of geology of the face. In
geological mapping conditions like the dip and orientation of the foliation plane, joint and
cavities are noted. The measurement of the dip and orientation of these foliation and joints
are measured using the Brunton compass. Via these values the Q-value of the rock is found

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out which is vital for determining rock type, excavation class which in turn gives the rock
support classification.

2.4.9 Installation of Support

From the result of geological mapping the rock type is determined which in turn provides for
the type of support to be installed.

Table 7: Classification of Rock Type based on Q value

Q- value Range Rock Type
400<Q≤1000 Exceptionally Poor
100<Q≤400 Extremely Poor
40<Q≤100 Very Good
10<Q≤40 Good
4<Q≤10 Fair
1<Q≤4 Poor
0.1<Q≤1 Very Poor
0.01<Q≤0.1 Extremely Poor
0.001<Q≤0.01 Exceptionally Poor

Table 8: Rock Support based on Q value for Penstock Tunnel

Rock Rock Support

Support Q-value Preliminary
Class Rockbolts Shotcrete Steel Ribs
Support
D20, L=1.5m,
CLASS I Q>4 - - -
Spot bolting
D20, L=1.5m,
CLASS II 1<Q<4 1.6m spacing - - -
at crown
D20, L=1.5m, Plain 5cm
CLASS III 0.5<Q<1 1.5m spacing thick at - -
at crown crown
Fibre 5cm
D20, L=1.5m,
thick at
1.4m spacing
CLASS IV 0.1<Q<0.5 crown and - -
crown and
wall
wall
D20, L=1.5m, Fibre 10cm
1.2m spacing thick at
CLASS V 0.01<Q<0.1 - -
crown and crown and
wall wall
75*100m
D20, L=1.5m, Fibre 15cm m @ 1m
1 m spacing thick at only in
CLASS VI Q<0.01 -
crown and crown and high
wall wall seepage
area

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Table 9: Rock Support based on Q value for Penstock Tunnel

Rock Initial Rock Support
Suppor Q-value Shotcret Concrete
t Class Rockbolts Steel Ribs Invert
e Lining
D20, Fibre
20cm thick
CLASS L=2m, 5cm thick
Q>4 - C20/25 -
I Spot at crown
grade
bolting and wall
D20,
L=2m, Fibre
20cm thick
CLASS 1.8m 5cm thick
1<Q<4 - C20/25 -
II spacing at at crown
grade
crown and and wall
wall
D20,
L=2m, Fibre
20cm thick
CLASS 1.6m 5cm thick
0.5<Q<1 - C20/25 -
III spacing at at crown
grade
crown and and wall
wall
D20, Fibre
L=2m, 10cm
20cm thick
CLASS 1.4m thick at
0.1<Q<0.5 - C20/25 -
IV spacing crown
grade
crown and and 5cm
wall wall
D20, Fibre
L=2m, 15cm 20cm thick
20cm thick
CLASS 1.2m thick at C20/25
0.01<Q<0.1 - C20/25
V spacing crown grade on all
grade
crown and and 10 at sides
wall wall
D20, 75*100m
Fibre
L=2m, m @ 1m
15cm 30cm thick 30cm thick
CLASS 1m only in
Q<0.01 thick at C20/25 C20/25
VI spacing high
crown grade grade
crown and seepage
and wall
wall area

2.4.10 Excavation for incline in penstock

For the purpose of incline excavation that is present in the penstock tunnel, Alimak has been
used. Alimak is based on a lift-type climber, which has a platform, safety canopy, lift basket
and motor. The climber travels on the rails that are foxed onto the rock wall and is driven by
compressed air. The water and air lines are attached to the rail. For the purpose of excavation
firstly a pilot hole of 2.20m is bored which is that increased to the required size of
excavation. During our internship period Alimak was being used in the penstock tunnel in the
d/s.

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The five steps of a cycle are:

i. Drilling, this is done from the platform of the Raise Climber. The platform is
adapted to fit the size and shape of the raise.
ii. Loading is also done from the platform.
iii. Blasting is triggered from a well-protected location at the bottom station.
iv. Ventilation. Nitrogen gases and dust created by the blast are cleared by spraying
a mixture of water and air through pipes in the guide rail.
v. Scaling. When the air has been cleared the crew can ascend in the Raise Climber
to the face, scale and install a new guide rail section, all under protection of the
safety roof.

2.4.11 Rock Support

2.4.11.1 Rib Support
Steel Ribs are primary support placed after excavation in the tunnel section. It allows for the
load distribution of load from the crown and overburden on to the ground thus acting as
reinforcement for the tunnel. Steel Ribs are mainly placed at weak zones and zones where
squeezing occurs.

In case of SHEP, steel ribs are provided in HRT in class VI rock type i.e. Q<0.01 and in
zones with high seepage zones. Steel ribs of (I-section) have been used in SHEP at spacing of
1m. Such steel ribs are fabricated in pieces to be tied to each other by plates and nut bolts
(four pieces, two legs below spring level and two arches). For further support the ribs are
bolted to the rocks via anchor rods of 1m long, 20mm diameter steel rod and two consecutive
ribs are connected with 16mm diameter, 1m long steel rods placed as per the drawings.

2.4.11.2 Backfilling Figure 11: Rib Installation

The tunnels are intended to be backfilled with a mixture of concrete, which is compacted in
situ. The overall requirement on backfilling is that the backfilled tunnel shall have a hydraulic
conductivity, which is equal to that of the repository rock on average.

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For SHEP the grade of concrete used for backfill was C12/15. The concrete mix was prepared
outside the tunnel and was transported in the required site via a loader. Then the concrete was
placed on a concrete pump which utilized compressed air for pumping the concrete. Water
was added in the concrete to make it pumpable and thus backfilling was done. During the
preparation of concrete mix for backfilling the observed value of slump was not in the region
of that specified however due to presence of seepage in the tunnel and complying to the fact
that water was still to be added to the mix in the tunnel for pumping, it was informed to us
that the w/c ratio had been decreased taking into consideration site conditions, thus no
modification was made to the concrete mix.

Figure 12: Backfilling

2.4.11.3 Shotcreting
Shotcreting orSprayed concreting refers to the process of spraying a mix of cement, sand and
fine aggregate through a hose projected at a very high velocity on the surface of the rock face.
Shotcreting may be of types plain or fibres reinforced or wire mesh reinforced. Shotcrete in
SHEP contained Micro silica as admixture and Sikament 170 as plasticizer to reduce the
quantity of water and to improve the pump ability of concrete.

In the field,fibreof 3cm in length and 0.25 mm in diameter has been used for fibre shotcrete.
Fibre shotcrete has been used in rock types of HRT and also penstock tunnel except Rock
Class I,II,III. In class III plain shotcrete has been used. Welded wire fabric of dimension
150mm x 150mm x 6 mm have been used for wire mesh reinforced shotcrete as required.

For the process of shotcreting concrete mix is prepared outside of the tunnel, where concrete
mixer prepares the mix, which is then loaded upon a loader and transported in to the required
site where it is placed in to the shotcrete machine and is sprayed. The thickness of shotcrete
varies according to the site condition and the rock type.

2.4.11.4 Invert Concrete and Concrete Lining

For the purpose of requiring additional support and strength to the tunnel Concrete lining is
done where necessary. Invert Lining is to be done on the invert of the tunnel. For both of
these a C20/25 grade of concrete has been used.

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Invert lining has been done on the entirety of the HRT. Concrete lining is only done for
sections with weak zones, shear zones, areas prone to squeezing.

2.4.11.5 Rock Bolts

Rock Bolts are used for provision of immediate support. In SHEP fully grouted deformed
steel bars bolt of 20mm diameter have been used, the length of rock bolts vary according to
the rock support condition governed by the rock type. There is the provision for resin grouted
bolt but in field ordinary cement grouted bolt have been used. The bolts are threaded at the
end for tightening the bearing or face plate by using nut. The bearing plate of dimension
150mmX150mmX8mm has been placed. Washer is placed before the nut. If required the
bearing plate of 250mm X 250mm X 15mm or 200mm X 200mm X 10mm should be used.
The nut of grouted rock bolts is to be tightened to achieve a force at the anchor plate of
approximately 20 kN.

For the test of Rock Bolts, pull out test is carried out on the bolts. In a predefined section of
tunnel 50 rock bolts are tested and if 3 of those fail to meet the required criteria the rock bolts
fail the pull out test. The pull out test is carried out by the use of the hydraulic jack with a pull
force of 127 kN.If applying this creates the displacement of 8 mm then the rock said to be
failed. The hydraulic jack presses the face plate and pulls the bolt.

However we were not able to test for the rock bolts due to lack of concrete padding on the
base plates of the rock bolts.

Figure 13: Rock Bolts

2.4.11.6 Grouting
Grouting is the method in which a solidifying liquid is pressure-injected into the rock mass in
order to prevent ground water leakage into the tunnel.The grout material is composed of
cement, water, sand and admixture.

We were to see grouting carried out in rock bolts for consolidation. This grout fills these
voids, thus stabilizing and strengthening the soil. Pressure Grouting favors control of the
amount of grout and has many applications. The purpose of grouting can be either to
strengthen a formation or to reduce water flow through it.

For the purpose of rock bolt grouting cement slurry with compressive strength of 45MPa at
28 days must be used.

Table 10: Materials for Grout Mix

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Material
Cement Agrakanchi OPC
Plasticizer Sikament 1016 NS-0.9% by wt. of cement
Admixture Intraplast-0.25%
Table 11: Composition of Grout Mix
Material(kg) Cement(kg) Water(kg) Plasticizer(kg) Admixture(kg)
Wt for trial mix 3.5 1.229 0.0315 0.0087
Wt per bag 50 17.5 0.45 0.125

The rock bolts bolted onto the tunnel have been tied up with two pipes, one of which reaches
the end of the bolt whereas another one reaches 50 cm inside the bolt.

Grouting Procedure:

1. Grout mix is prepared on site, by placing specified amount of cement, water,

plasticizer and retarder.
2. These are mixed by use of hand held mixer.
3. The grout mix is then poured into the grouting machine; grouting machine consists of
two hoses one of which is used to control the grout pressure and another for grouting.
4. The grout mix is then injected into the one of the pipe extruding out of the rock bolt
until it spills out of another pipe, thence the pipe is tied into a knot.
5. The same process is continued in the other pipe then the pipe is tied into a knot.

(Detail Drawings of rock support in HRT and penstock tunnel have been provided in
ANNEX I)

2.4.12 Problems encountered during Tunneling

2.4.12.1 Seepage
This was one of the major problems in felt during tunnel construction. It was much more
prevalent in Audit 1 and HRT inlet. The seepage had filled the ground with water up to knee-
level in some of the areas. Flowing water might carry materials into newly excavated
openings, causing general instability in the mass of rock. Additionally, water can change the
ground’s physical properties and behavior, making it unpredictable. The presence of water
makes handling of material difficult also transporting of material is made difficult.

2.4.12.2 Over break

Over break of rock mass may occur beyond the tunnel face which may be caused due to
blasting or even poor rock mass quality. These may occur in high stress environment, shear
and weak zones. In order to prevent over break shotcreting is done on the newly excavated
surface to provide temporary support.

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We observed over break in audit 1 leading towards the HRT. This was due to presence of
cavity in the rock mass. Due to this presence of cavity the weak rock mass fell onto the base
of tunnel which required for mucking.

For this problem of over break, the measures that were taken are listed below:

1. Shotcreting on the rock mass fallen from the cavity and around the cavity.
However even though shotcreting was carried out the falling of rock mass continued
leading a huge cavity.
2. During rib installation it was decided that additional ribs would be provided for
additional support.
3. Spilling dowels of 25mm diameter,2.5m in length and 15 in no. were provided for
support and control of overbreak
4. Backfilling of the cavity is to be done using concrete of grade C12/15 after
construction of remaining tunnel. The amount of backfill required was calculated by
survey.

ure 15: Overbreak

4 in tunnel Figure 16: Spilling dowels for support in
Overbreak

2.4.12.3 Lack of concrete padding for rock bolt pull out test
Though pull out test was intended to be carried out in the surge shaft, it could not be carried
out due lack of concrete padding on the base of rock bolts. Rock bolts had been marked
previously which required concrete padding for rock bolt pull out test, but it had not been
done thus rock bolt pull out test had been cancelled until concrete padding was done.

2.5 Surface Penstock

The Surface Penstock starts from the chainage of 4+405.15m with a pipe diameter of 2.2m.
The surface penstock consists of two bends of radius 11m on vertical and other horizontal.
These bends are to be supported by two anchor blocks on each bends constructed using
C16/20 grade concrete. The penstock is placed at a downward slope of 1:4.82 to the chainage
of 4+520.044m. The diameter of penstock varies from 2.2m diameter to 1.8m and the
transition occurs at 4+471.46m to 4+473.42m and then to 1.06m transition occurring from
4+515.304m to 4+517.304m.

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Table 12: Detail of Bends in Surface Penstock

Bend Start of Bend in End of Bend in Radius of Bend(m)
chainage (m) Chainage (m)
Bend 1(Vertical) 4+405.87 4+407.91 11.00
Bend 2(Horizontal) 4+499.60 4+506.864 11.00
(Detail Drawings have been provided in ANNEX I)

2.6 Powerhouse
The structural complex where all the equipment’s for providing electricity are suitably
arranged is a powerhouse. Two basic requirement of powerhouse planning are functional
efficiency and aesthetic beauty. One of the choices is whether to locate the powerhouse in a
building above ground called as surface powerhouse or to locate it as the underground
powerhouse situated in caverns, excavated below the ground.

Bifurcation refers to wye division of penstock to divide the flow symmetrically or

unsymmetrically into two units of turbine for maintaining economical, technical and
geological substrates. Particularly, water shows irrelevant behavior when there is a sudden
change in flow direction, which results into the transition of the static and dynamic behavior
of the flow. Hence, special care and design considerations are required both hydraulically and
structurally. The transition induced losses and extra stresses are major features to be
examined.

The powerhouse of Sanjen HEP is proposed in the right bank of the ChilimeKhola very
close to the headworks of existing Chilime Power Plant at Chilime Village.

The powerhouse will be equipped with three units of Vertical Pelton turbines and matching
synchronous generators.The surface penstock, with the C L at an elevation of 1745.00 m,
enters the powerhouse and the penstock is bifurcated at chainage of 4+515.304 m changing
the penstock diameter from Ф1.8m to Ф1.5m at 1st unit. Second bifurcation is done at
chainage of 4+529.674m changing Ф1.5m to Ф1.06m at 2nd unit and 3rd unit. Each of these
penstock pipes are attached with manifold pipe provided with 4 nozzles each which rounds
the turbine unit in order to hit the turbine from every direction. These arrangements are all
covered with mass concreting of strength C25/30 with total volume of 480 m3.

The sizing of the powerhouse is done in such a way that it encompasses all the machines
equipment and provides sufficient space for maintenance and easy installation. Entrance to
the powerhouse building is through a 2m wide rolling shutter gate and the service bay is
immediately after the entrance gate.

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Figure 17: Powerhouse SHEP

(Detail Drawings have been provided in ANNEX I)

The powerhouse of SanjenUHEP is designed to have 3 turbine units of Horizontal Francis

Turbine. Compared to Sanjen HEP, the penstock pipe is underground and is directly entered
to the powerhouse where the pipe is bifurcated at three points creating a provision of EDV
(Energy Dissipating Valve ). The sole purpose of EDV provision is for cascading the Sanjen
UHEP to Sanjen HEP. The bifurcation is done at 3 points and the elevation of the C L of the
penstock pipe is 2184.80 m while that of EDV pipe is lowered upto 2183.20m.

Advantages of EDV pipe are:

- Cascading the upper and lower HEP.
- Preventing generation of the power from the lower HEP even when upper HEP is
undergoing maintenance.

2.6.1 Mass Concreting

Mass Concrete is any volume of concrete with dimensions large enough to require that
measures be taken to cope with the generation of heat from hydration of the cement and
attendant volume change to minimize cracking.

The Sanjen HEP underwent mass concreting in the area covering the bifurcated penstock
pipe as shown in the plan below. The whole mass concreting was carried out in 3 stages. First
the concreting was done upto the height of 1.3m enclosing the volume of 200m 3 which
almost covered the penstock pipe. After the completion of the concreting, the concrete was
allowed to set and cured for 7 days. The shear wall at sides and the top of mass concrete were
chipped for good second stage concreting. The second stage concreting was performed after 7
days which was of height 0.8m enclosing volume of 90m 3. Similarly, the third stage
concreting enclosed the volume of 190m 3 with depth of 1.2m. The total volume of the mass
concrete was 580m3 and the strength of the concrete was C25/30.

For elevation 1743.40m – 1744.70m

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Table 13: Source of material of bifurcation area in Power House For elevation 1743.40m –
1744.70m

Material
Cement 410 kg (Agrakhanchi OPC)
Coarse Aggregate (25 mm down) 876.96 kg (HH Cruher Plant (80%))
Coarse Aggregate (10mm down) 219.24 kg (HH Crusher Plant (20%))
Sand 643.8 kg (Powerhouse area sand washing plant)
Admixture 3.28 kg (Hind Plast Super-160-0.8%)
Retarder 2.05 kg (Hind Plast Super-R-0.5%)
Water 157.44 kg
W/C ratio 0.384
Table 14: Compressive Strength of 7 days concrete of bifurcation area in Power House for
elevation 1744.70m – 1745.50m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 9 16 8338 471 475.95 21.15
2 May May 7 days 8360 552 556.10 24.71
3 2019 2019 8168 627 630.34 28.01
Average Strength 24.62

For elevation 1744.70m – 1745.50m

Table 15: Source of material of bifurcation area in Power House for elevation 1744.70m –
1745.50m

Material
Cement 410 kg (Agrakhanchi OPC)
Coarse Aggregate (25 mm down) 876.46 kg (HH Cruher Plant (80%))
Coarse Aggregate (10mm down) 219.24 kg (HH Crusher Plant (20%))
Sand 643.8 kg (Powerhouse area sand washing plant)
Admixture 3.28 kg (Hind Plast Super-160-0.8%)
Retarder 2.05 kg (Hind Plast Super-R-0.5%)
Water 157.44 kg
W/C ratio 0.384
Table 16: Compressive Strength of 7 days concrete of bifurcation area in Power House for
elevation 1744.70m – 1745.50m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 16 23 8272 708 710.57 31.58
2 May May 7 days 8232 584 587.77 26.12
3 2019 2019 8236 725 627.41 32.32
Average Strength 30.00

For elevation 1745.50m – 1746.70m

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Table 17: Source of material of bifurcation area in Power House for elevation 1744.70m –
1745.50m

Material
Cement 410 kg (Agrakhanchi OPC)
Coarse Aggregate (25 mm down) 876.96 kg (HH Cruher Plant (80%))
Coarse Aggregate (10mm down) 219.24 kg (HH Crusher Plant (20%))
Sand 643.8 kg (Powerhouse area sand washing plant)
Admixture 3.28 kg (Hind Plast Super-160-0.8%)
Retarder 2.05 kg (Hind Plast Super-R-0.5%)
Water 157.44 kg
W/C ratio 0.384

Table 18: Compressive Strength of 7 days concrete of bifurcation area in Power House for
elevation 1744.70m – 1745.50m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 21 28 8320 474 478.92 21.28
2 May May 7 days 8408 471 475.95 21.15
3 2019 2019 8272 448 453.20 20.14
Average Strength 20.86

Process Involved in concreting

 First the materials ( sand, aggregate ) are loaded in the batching plant by the help of
excavator.
 Then, the plant automatically batches the materials by weight which is controlled
from the control panel.
 The mix is transferred to the mixer above where cement, water, admixtures and
retarders are mixed.
 The final concrete mix is passed to the Transit Mixer.
 The concrete is maintained in the liquid through rotation of the drum about its own
axis.
 The concrete is discharged to the concrete pump which was outside the powerhouse.
 The concrete placed in the pump is pumped through piston mechanism.
 The concrete pumped is reached to places required with the hose pipe connected to
the concrete pump.
 The hoses are interconnected or detached as per the length required to reach the
destination.
 The concrete placed in the powerhouse are spread to the corners and places where the
reinforcements are compact with the help of vibrator.
 The concrete is allowed to set once the whole concreting is finished.

Problems Encountered during Concreting

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 Problem in batching plant like the chain problem was encountered, which resulted in
delay in completion of concreting.
 Choking of the concrete in the concrete pump was encountered.
 Due to lesser w/c ratio, the workability of the concrete was decreased due to which
the concrete was stuck in the hose pipe than to reach the concreting place.
 Due to complex reinforcement design of the staircase, there was difficulty in using the
vibrator properly in the staircase.
 While concreting of the slab was carried out, the surface was to be levelled. But due
to the shear wall the difficulty in the work was increased for the surveyor.

2.7 Generator Hall

The generator hall is 34.0 m long and 8.0 m wide and 10m high. The powerhouse crane spans
8.0 m and is supported on reinforced concrete columns and beams. The floor in the hall will
be finished with acoustic sound absorption material.

2.8 Control room

Control room and office facilities are provided at downstream of the machine hall at an
elevation of 1754.0 mamsl. The control room looks after the generator hall and contains all
the necessary equipment to control the powerhouse.

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CHAPTER 3

CONSTRUCTION EQUIPMENTS

3.1. Grouting Pump

Grout Pump is the equipment used for spraying grout mix with high pressure to the
supporting works in tunnel, foundation and soil-rock, embed rebar's in masonry walls,
connect sections of pre-cast concrete and seal joints. Grout is generally composed of a
mixture of water, cement, sand &sometimes fine gravel.

Application

Grouting is the process of pumping a cement or chemical grout into soft or weak strata of soil
or interconnected pore or voids whose neither configuration nor volume is known. This grout
fills these voids, thus stabilizing and strengthening the soil. Pressure Grouting favors control
of the amount of grout and has many applications. One of these includes support for existing
structures or where foundations have shifted. The greatest use of pressure grouting is to
improve geomaterials (soil and rock).The purpose of grouting can be either to strengthen a
formation or to reduce water flow through it. It is also used to correct faults in concrete and
masonry structures. It is also a key procedure in the creation of post-tensioned prestressed
concrete, a material used in many concrete bridge designs, among other places.

Figure 18: Pressure Grouting

3.2. Hydraulic Excavator

Hydraulic Excavators are heavy construction equipment used to (excavate forcefully with
hydraulic system) various types of soils above and below its level as well for loading in dump
trucks. All movement and functions of a hydraulic excavator are accomplished through the
use of hydraulic fluid, with hydraulic cylinders and hydraulic motors.

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Among the two types of excavator namely Crawler and Wheel, Crawler Excavator was
equipped in the construction site. The Crawler runs in two endless tracks (chain wheel
system). It was preferred to wheel system in case of poor soil due to the large contact of
tracks and in hilly areas.

Figure 19: Hydraulic excavator at powerhouse site

3.3. Concrete Batching Plant

Concrete Batching Plant, also known as batch plant, batching plant or concrete plant is
equipment that combines various ingredients to form concrete. Some of these inputs include
water, air, admixtures, sand, aggregate (rocks, gravel, etc.), cement, etc. There are two main
types of concrete plants: Dry mix plants and Wet mix plants.

Wet Mix Plant was the one equipped at the construction site. The inputs provided were
cement, sand, crushed stone, water, admixture and retarder. Hind Plast Super was the
admixture and the retarder used. The calculated amount of the required materials is fed into
the plant and mixed by the agitator. The volume of the agitator is 0.35 m 3. After the mixing
done in the ready-mix, the mixed material is transported to the TM for further agitation till
the material reaches the site for concreting the structure.

Figure 20: Concrete Batching Plant

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3.4. Transit Mixer

Transit Mixer (TM) is the equipment used for transporting concrete/mortar or ready-mix
material from a concrete batching plant directly to the site where it is to be utilized. It is
loaded with dry material and water. The interior of the transit drum is fitted with a spiral
blade able to move in two directions. During clockwise movement, drum is charged with
concrete and in counterclockwise movement, concrete is discharged out from the drum.

There were 2 TM equipped for transporting the concrete from the batching plant at the site
for rapid concreting process. The capacity of the TM was about 6 m3.

Figure 21: Transit Mixer

3.5. Sand Washing Plant

These are the equipment designed for washing sand and recover the most part of the water
used during the process.

In Sanjen HEP, there is the traditional sand washing plant in use. In the plant, the materials
are placed over the sieve with the excavator and are washed with the water for sand to pass
through the sieve and separate out the aggregates. The water mix is passed through a
constructed canal to a pool where the washed sand is collected and deposited.

Figure 22: Sand Washing Plant

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3.6. Aggregate Crushing Plant

A crushing plant is the heavy machinery used for rock crushing. It has different stations
(primary, secondary, tertiary, ...) where different crushing, selection and transport cycles are
done in order to obtain different stone sizes or the required aggregates.

The plant equipped at Sanjen HEP can produce the aggregates of size ranges like………….

Figure 23: Aggregate Crushing Plant

3.7. Concrete Pump

A concrete pump is a machine used for transferring liquid concrete by pumping. There are
two types of concrete pumps namely Boom Pump and Line Pump.

The one used at Sanjen HEP site is Line pump. This pump required steel or flexible concrete
placing hoses to be manually attached to the outlet of the machine. Those hoses are linked
together and lead to wherever the concrete needs to be placed. The concrete is placed on the
pump from the Transit Mixer and the placed concrete is pumped with piston pump through
the hoses to the point.

Figure 24: Concrete pump during mass concreting in powerhouse

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3.8. Single Drum Vibratory Roller

These are Steel Drum Roller but with vibratory facilities which enhance the performance and
efficiency of the roller. It increases density of the materials faster than the ordinary Drum
Roller. It is desirable to use in clay and sandy soil which can better be compacted by
vibration.

The roller used in Sanjen HEP was Single Drum Vibratory Roller for the compaction of soil
in the power house is upto the elevation of 1749.80 m amsl.

Figure 25: Single Drum Vibratory Roller

3.9. Alimak
The Alimak method is based on a lift type climber, which has a platform, safety canopy, lift
basket and motor. The climber travels on rails that are fixed onto the rock wall and is driven
by air, or an electric or diesel motor. The water and air lines are attached to the rail. The
Alimak method represents the first mechanized form of raise building. It is more efficient
than the traditional raise building and is much safer as the work is always performed under
protective canopy. The Alimak method is a relatively inexpensive alternative for construction
sites that have a few variable length raises.

The Alimak method raises between levels in a safe and effective manner. Drilling, loading
and blasting are all performed from the platform of the Raise Climber, which is adapted to fit
the precise dimensions and shape of the raise.

The Alimak Method

The Alimak Method consists of five steps which together make up a cycle. The Raise
Climber serves both as working platform and as a means of transport up to the work face.

It runs on a guide rail anchored to the hanging wall. Using curved guide rails the direction
of travel can be changed at any time; forward, backward, or sideways.

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Figure 26:

Alimak Method

3.10. Wheel Loader

A loader is a heavy equipment machine used in construction to move aside or load materials
such as asphalt, demolition debris, dirt, snow,etcinto or onto another type of machinery (such
as a dump truck, conveyor belt, feed-hopper, or railroad car).There are many types of loader,
which, depending on design and application and the one used at Sanjen HEP is Wheel Loader
with and without Backhoe.

Generally, the loader without backhoe is being used for transporting concrete mix into the
tunnel and for mucking purpose while the loader with backhoe is being equipped for the
surface construction works ( i.e, placing materials on batching plant, placing materials on
tippers for transporting to the site, etc )

Figure 27: Wheel Loader without backhoe

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CHAPTER 4

QUALITY CONTROL/ASSURANCETESTS

4.1. Trial Mix of Concrete

Any change in type or source of cement or aggregates during the progress of the Works
requires fresh trial mixes to be prepared by the Contractor and to be approved by the
Engineer. Not less than 28 days before the date on which the Contractor proposes to use a
mix in the Permanent Works, in the presence of a representative of the Engineer Contractor
should prepare six separate batches to the full capacity of the mixer of the proposed mix,
using the materials, plant and equipment which will be used for the Permanent Works.
Sufficient samples shall be taken from each batch to prepare the test specimen. Each class of
concrete shall have a trial mix consisting of 9cubes of standard size of
150mm*150mm*150mmaccording to the specification made from 6 batches. Compressive
testing at 3 days, 7 days and at 28 days is carried out.

The trial mixes shall be deemed as approved if the characteristic strength fck so determined is
greater than the specified compressive strength. Based on the results of the tests on the trial
mixes, the Contractor shall submit full details of his proposals for mix design to the Engineer,
including the type and source of each ingredient, the proposed proportions of each mix and
the results of the tests on the trial mixes.

This new trial fix was formulated since aggregates from a different crusher site were intended
to be used. This trial mix was for strength of C16/20.

Figure 28: Preparation of Trial Figure 29: Pouri

Mix concrete in cub
Table 19: Source of Materials of Trial Mix for PCC in Power House

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Material
Cement Agrakhanchi OPC
Coarse Aggregate (25 mm down) HH Cruher Plant (80%)
Coarse Aggregate (10mm down) HH Crusher Plant (20%)
Sand Powerhouse area sand washing plant
Admixture Sikament 1016 N/S

Table 20: Composition of Trial Mix for PCC in Power House

Coarse Fine Concrete

Batch Aggregate (kg) Admixtu Water Air
Water Cement Aggre Temperatu
volume re Tempera Temperature
(kg) (kg) 25 mm 10mm gate re after
(m3) (kg) ture (°C)
down down (kg) mix(°C)
3.67
(1% by
1 171.02 367.00 854.41 213.60 712.00 weight 20.5 24.1 24.1
of
cement)
0.038
(for 9 6.51 13.946 32.467 8.116 27.056 0.139 20.5 24.1 24.1
cubes)

After preparation of the concrete mix 9 cubes were prepared in a standard mouldof
150mm*150mm*150mm. Slump test was consequently carried out for the concrete mix
which resulted in a slump of 75 mm which was to be obtained between 50mm-100mm. Then
compressive strength test was to be carried out for 3, 7 and 28 days.

Table 21: Compressive Strength of 7 days concrete for PCC in Power House

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 24 27 8528 547 551.16 24.49
2 May May 3 days 8618 537 541.26 24.05
3 2019 2019 8472 572 575.89 25.59
Average Strength 24.71

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4.2. Compressive Strength Test

Samples are to be cured and tested, three samples being tested at 7 days and the other three
samples at 28 days. The concrete cubes tested at 7 days are intended to be indicative of the
strength only, whereas the cubes tested at 28 days shall be taken to represent the concrete
placed in the Works. The concrete shall be accepted if the 28 day characteristic strength
determined exceeds the specified compressive strength.

The standard moulds vary for concrete and for grout mix. For concrete mix the standard
mould size is 150mm*150mm*150mm whereas for grout mix the mould size is
50mm*50mm*50mm.

For the purpose of the test an analogue compression test machine of capacity 1500 KN was
present in the lab. This compressive testing machine is needed to be calibrated after one year
which is done by Pulchowk Campus which was last calibrated on 13 August 2018.

Figure 30: Placement of concrete Figure 31: Preparation of Cubes

in standard cube moulds for compression test for grout mix

Figure 32: Compressive Strength

Test

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Compressive test of concrete for Power House Shear Wall-C25/30 (E.L. 1747.50-1748.00m)
(C-256)

Table 22: Source of Materials of concrete for Power House Shear Wall(E.L. 1747.50-
1748.00m)

Material
Cement Agrakhanchi OPC
Coarse Aggregate (25 mm down) HH Cruher Plant (80%)
Coarse Aggregate (10mm down) HH Crusher Plant (20%)
Sand Powerhouse area sand washing plant
Admixture Hind Plast Super-160 (0.8% by wt. of cement)
Retarder Hind Plast Super-R (0.5% by wt. of cement)

Table 23: Composition of concrete for Power House Shear Wall(E.L. 1747.50-1748.00m)

Coarse Fine Water

Batch Aggregate (kg) Admixtu
Water Cement Aggre Retarder Cement Slump
volume re
(kg) (kg) 25 mm 10mm gate (kg) Ratio (mm)
(m3) (kg)
down down (kg) (%)
1 157.44 410.00 876.96 219.24 643.8 3.28 2.05 0.384 130

Table 24: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1747.50-1748.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 10 17 8130 379 384.69 17.09
2 April April 7 days 8260 396 401.70 17.85
3 2019 2019 7990 430 435.39 19.35
Average Strength 18.09

Table 25: Compressive Strength of 28 days concrete for Power House Shear Wall(E.L.
1747.50-1748.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 10 8 8318 930 932.61 44.45
2 April May 28 days 8382 862 864.13 38.40
3 2019 2019 8330 847 849.03 37.73
Average Strength 39.19
Compressive test of concrete for EDV Power House in SUHEP-C25/30

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Table 26: Source of Materials of concrete for EDV Power House in SUHEP

Material
Cement Agrakhanchi OPC
Coarse Aggregate (30 mm down) Quarry, Cruher Plant
Sand Quarry, Headwork Site
Plasticizer Markplast SP-10
Table 27: Composition of concrete for EDV Power House in SUHEP

Fine Water
Batch Admixtu
Water Cement Coarse Aggre Cement Slump
volume re
(kg) (kg) Aggregate (kg) gate Ratio (mm)
(m3) (kg)
(kg) (%)
1 164 437 1095 730 7 0.375 140

Table 28: Compressive Strength of 7 days concrete for EDV Power House in SUHEP

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 12 19 8164 690 690.29 30.68
2 April April 7 days 8168 700 700.10 31.12
3 2019 2019 8156 680 680.48 30.24
Average Strength 30.70

Table 29: Compressive Strength of 28 days concrete for EDV Power House in SUHEP

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 12 10 8298 980 978.40 43.48
2 April May 28 days 8200 990 988.90 4395
3 2019 2019 8280 990 988.90 43.95
Average Strength 43.80

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Compressive test of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+274 to 0+294)m
-C28/35( C-260)

Table 30: Source of Materials of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+274
to 0+294)m

Material
Cement Sagarmatha OPC
Coarse Aggregate (10 mm down) SUHEP Cruher Plant
Sand Powerhouse area sand washing plant
Admixture Micro silica (10% by wt. of cement)
Plasticizer Sikament 170(1.5% by wt. of cement)
Fine Water
Batch Admixt
Water Cement Coarse Aggre Plasticier Cement Fiber Slump
volume ure
(kg) (kg) Aggregate (kg) gate (kg) Ratio (kg) (mm)
(m3) (kg)
(kg) (%)
1 247 540 334 1094 54 8.10 0.416 48.6 175
Table 31: Composition of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+274 to
0+294)m

Table 32: Compressive Strength of 7 days concrete for Fiber Shotcrete in HRT Inlet Tunnel
d/s (0+274 to 0+294)m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 27 4 7782 430 435.39 19.35
2 April May 7 days 7794 426 431.43 19.17
3 2019 2019 7818 434 439.34 19.52
Average Strength 19.35

Table 33: Compressive Strength of 28 days concrete for Fiber Shotcrete in HRT Inlet Tunnel
d/s (0+274 to 0+294)m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 27 25 8046 1032 1034.09 45.96
2 April May 28 days 7892 892 894.34 39.75
3 2019 2019 7850 1017 1019.56 45.31
Average Strength 43.67

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Compressive test of concrete for Power House Shear Wall-C25/30 (E.L. 1748.00-1749.00m)
(C-262)

Material
Cement Agrakhanchi OPC
Coarse Aggregate (25 mm down) HH Cruher Plant (80%)
Coarse Aggregate (10mm down) HH Crusher Plant (20%)
Sand Powerhouse area sand washing plant
Admixture Hind Plast Super-160 (0.8% by wt. of cement)
Retarder Hind Plast Super-R (0.5% by wt. of cement)
Table 34: Source of Materials for Power House Shear Wall(E.L. 1748.00-1749.00m)

Table 35: Composition of concrete for Power House Shear Wall(E.L. 1748.00-1749.00m)

Coarse Fine Water

Batch Aggregate (kg) Admixtu
Water Cement Aggre Retarder Cement Slump
volume re
(kg) (kg) 25 mm 10mm gate (kg) Ratio (mm)
(m3) (kg)
down down (kg) (%)
1 157.44 410 876.96 219.24 643.8 3.28 2.05 0.384 135

Table 36: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 29 6 8232 495 499.70 22.21
2 April May 7 days 8278 533 537.30 23.88
3 2019 2019 8230 453 458.14 20.36
Average Strength 22.15

Table 37: Compressive Strength of28 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 29 27 8316 943 945.70 42.03
2 April May 28 days 8330 907 909.45 40.42
3 2019 2019 8356 1015 1017.63 45.22
Average Strength 42.55

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Compressive test of concrete for Power House Shear Wall-C25/30 (E.L. 1748.00-1749.00m)
(C-261)

Table 38: Source of Materials for Power House Shear Wall(E.L. 1748.00-1749.00m)

Material
Cement Agrakhanchi OPC
Coarse Aggregate (25 mm down) HH Cruher Plant (80%)
Coarse Aggregate (10mm down) HH Crusher Plant (20%)
Sand Powerhouse area sand washing plant
Admixture Hind Plast Super-160 (0.8% by wt. of cement)
Retarder Hind Plast Super-R (0.5% by wt. of cement)
Table 39: Composition of concrete for Power House Shear Wall(E.L. 1748.00-1749.00m)

Coarse Fine Water

Batch Aggregate (kg) Admixtu
Water Cement Aggre Retarder Cement Slump
volume re
(kg) (kg) 25 mm 10mm gate (kg) Ratio (mm)
(m3) (kg)
down down (kg) (%)
1 157.44 410 876.96 219.24 643.8 3.28 2.05 0.384 135

Table 40: Compressive Strength of 7 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 29 6 8410 501 505.64 22.47
2 April May 7 days 8310 468 472.44 21.02
3 2019 2019 8410 472 476.44 21.20
Average Strength 21.56

Table 41: Compressive Strength of 28 days concrete for Power House Shear Wall(E.L.
1748.00-1749.00m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 29 27 8276 1019 1021.50 45.40
2 April May 28 days 8312 964 966.85 42.97
3 2019 2019 8290 955 957.78 42.56
Average Strength 43.64

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Compressive test of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s (0+409 to 0+417)m
-C28/35( C-274)

Material
Cement Sagarmatha OPC
Coarse Aggregate (10 mm down) SUHEP Cruher Plant
Sand Powerhouse area sand washing plant
Admixture Micro silica (10% by wt. of cement)
Plasticizer Sikament 170(1.5% by wt. of cement)

Table 42: Source of Materials of concrete for Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409
to 0+417)m

Table 43: Composition of Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409 to 0+417)m

Fine Water
Batch Admixt
Water Cement Coarse Aggre Plasticier Cement Fiber Slump
volume ure
(kg) (kg) Aggregate (kg) gate (kg) Ratio (kg) (mm)
(m3) (kg)
(kg) (%)
1 247 540 334 1094 54 8.10 0.416 48.6 175

Table 44: Compressive Strength of 7 days Fiber Shotcrete in HRT Inlet Tunnel d/s(0+409 to
0+417)m

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 20 27 8160 690 692.75 30.78
2 May May 7 days 8116 735 737.32 32.76
3 2019 2019 8054 708 710.57 31.58
Average Strength 31.70

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Compressive test of concrete for Adit 1 Backfill –C12/15 (0+595.0m)(C-273)

Table 45: Source of Materials of concrete for Adit 1 Backfill –C12/15 (0+595.0m)

Material
Cement Sagarmatha OPC
Coarse Aggregate (25 mm down) HH Cruher Plant (80%)
Coarse Aggregate (10mm down) HH Crusher Plant (20%)
Sand Powerhouse area sand washing plant

Table 46: Composition of concrete for Adit 1 Backfill –C12/15 (0+595.0m)

Coarse Fine Water

Batch Aggregate (kg)
Water Cement Aggre Cement Slump
volume
(kg) (kg) 25 mm 10mm gate Ratio (mm)
(m3)
down down (kg) (%)
1 187.03 317 1089.6 272.4 570 0.59 70

Table 47: Compressive Strength of 7 concrete for Adit 1 Backfill –C12/15 (0+595.0m)

Cast Test Load(KN Corrected

S.N. Age(days) Weight(gm) Strength(N/mm2)
Date Date ) Load(KN)
1 19 26 8210 370 375.68 16.69
2 May May 7 days 8218 375 380.69 16.91
3 2019 2019 8208 373 378.69 16.83
Average Strength 16.81

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4.3. Concrete Slump Test

Concrete slump test or slump cone test is to determine the workability or consistency of
concrete mix prepared at the laboratory or the construction site during the progress of the
work. Slump tests are to be carried out at the point of mixing and at the point of placing or as
often as necessary to verify and control consistency of the concrete. Slump tests are to be
made and recorded for every section of concrete being placed and for every sample sets.

Slump tests carried out in the site are done after the concrete mix has been prepared by the
batching plant. Thus some concrete mix was taken out from the batching plant for the slump
test to be carried out while the remaining was poured on to a transit mixer to be taken to the
concreting site.

Mold for slump test i.e. slump cone, non porous base plate, measuring scale, temping rod.
The mold for the test is in the form of the frustum of a cone having height 30 cm, bottom
diameter 20 cm and top diameter 10 cm. The tamping rod is of steel 16 mm diameter and
60cm long and rounded at one end.

The internal surface of the mouldis cleaned and greased. The mouldis placed on a smooth
horizontal non- porous base plate. The mould is filled in approximately 4 layers by tamping
each layer 25 times. The excess concrete Remove and the surface is level with a trowel.The
mortar or water leaked out between the mould and the base plate is to be cleaned. The mould
is raised from the concrete immediately and slowly in vertical direction.The slump is
Measure as the difference between the height of the mould and that of height point of the
specimen being tested.

Figure 33: Prepataion of Slump Figure 34: Concrete Slump after

Removal of Cone

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Table 48: Result of Slump Tests

S.N Observed Specific

Description of Slump Test Remarks
. Value(mm) Value
Concrete for Mass The observed value was
Concreting of powerhouse in the region of that
1 135 100-150
of SHEP specified thus the
concrete mix was okay
The observed value was
Concrete for concreting in in the region of that
2 140 100-150
EDV area specified thus the
concrete mix was okay
The observed value was
Concrete for Concreting of
in the region of that
3 bifurcation area in 110 100-150
specified thus the
powerhouse of SHEP
concrete mix was okay
The observed value was
Trial Mix concrete for in the region of that
4 70 50-100
PCC of powerhouse specified thus the
concrete mix was okay
The observed value was
not in the region of that
specified however due to
presence of seepage in
the tunnel and complying
to the fact that water was
still to be added to the
Concrete for Concreting at
5 20 50-100 mix in the tunnel for
rib till spring line at adit1
pumping, it was informed
to us that the w/c ratio
had been decreased
taking into consideration
site conditions, thus no
modification was made to
the concrete mix.

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4.4. Field Density Test

The field density test of soil is conducted in the field to know whether the specified
compaction is achieved or not. In our case the area outside of the powerhouse of SHEP was
being filled and compacted to required level of 1749.80m E.L. and was being compacted to a
grade of 2B. In this case Sand Replacement Method has been used.

In our case, a hole of 15 cm diameter hole and of 15 cm depth was dug in the site. The
compacted soil extracted from the hole was then weighed.Then it was passed through a
20mm sieve and the aggregate retained in 20mm sieve size were weighed. The standard sand
sample weighing 16 kg was kept in the sand pouring cylinder of diameter 15cm and height 45
cm and poured into the hole through the cone arrangement in the cylinder. The remaining
sand in the cylinder was weighed and in the site the wet soil moisture content is calculated.
The wet density as well as dry density of soil was calculated. Then samples of the compacted
soil were taken in can to be dried and finally calculate the moisture content and the relative
compactness. The test was done for two iterations.

Figure 35: Placement of

Figure 36: Removal of Soil to be
Appartaus
weighed and tested

Figure 38: Placement of Cylinder filled

with sand
Figure 37: Pouring of sand onto
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Field Density Test of compacted soil of powerhouse EL 1746 to 1747m

SN Description Unit Iteration 1 Iteration 2

VOLUME
1 Wt. of sand and apparatus before test gm 16000 16000
2 Wt. of sand residual and apparatus gm 12306 11770
3 Wt. of sand used (1-2) gm 3694 4230
4 Wt. of sand in cone gm 1276 1276
5 Wt. of sand in hole (3-4) gm 2418 2954
6 Sand Density gm/cc 1.335 1.335
7 Volume of hole (5/6) cc 1811.24 2212.73
DENSITY
8 Wt. of total wet soil gm 4220 5030
9 Wt. of soil 20 mm retained gm 974 758
10 Wt. of wet soil (8-9) gm 3246 4272
11 Volume of soil 20 mm retained (9/Sp. Gr=2.58) cc 337.52 293.79
12 Volume of soil passing 20 mm (7-11) cc 1433.72 1918.94
13 Wet density (10/12) gm/cc 2.264 2.226
14 Dry density (13/(Avg. moisture content+1)) gm/cc 2.102 2.080
MOISTURE CONTENT
Can no. B6 B7 B4 B3
15 Wt. of can + wet soil gm 88.37 96.11 111.53 100.94
16 Wt. of can + dry soil gm 83.04 91.32 106.41 94.62
17 Wt. of water (17-18) gm 5.33 4.79 4.62 6.32
18 Wt. of can gm 20.11 21.96 20.57 21.86
19 Wt. of dry soil (18-20) gm 62.93 61.36 56.34 72.76
20 Moisture Content (19/21*100) % 8.47 6.90 5.35 8.69
21 Avg. Moisture Content % 7.68 7.02
Table 49: Result of Field Density Test of compacted soil of powerhouse from EL 1746 to
1747m

Table 50: Summary of Result of Field Density Test of compacted soil of powerhouse from
EL 1746 to 1747m

Test No. Moisture Content (%) Density(gm/cc) Relative Compaction (%)

OMC Field Field MDD Field Specified
1 6.80 7.68 2.100 2.139 98.12 95
2 6.80 7.02 2.080 2.139 97.24 95

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Field Density Test of compacted soil of powerhouse EL 1747m to 1479.80m

Table 51: Result of Field Density Test of compacted soil of powerhouse from 1747 to
1749.80m

SN Description Unit Iteration 1 Iteration 2

VOLUME
1 Wt. of sand and apparatus before test gm 16000 16000
2 Wt. of sand residual and apparatus gm 12264 12368
3 Wt. of sand used (1-2) gm 3736 3632
4 Wt. of sand in cone gm 1276 1276
5 Wt. of sand in hole (3-4) gm 2460 2356
6 Sand Density gm/cc 1.335 1.335
7 Volume of hole (5/6) cc 1842.70 1764.79
DENSITY
8 Wt. of total wet soil gm 4174 4074
9 Wt. of soil 20 mm retained gm 810 1116
10 Wt. of wet soil (8-9) gm 3364 2958
11 Volume of soil 20 mm retained (9/Sp. Gr=2.58) cc 313.95 432.56
12 Volume of soil passing 20 mm (7-11) cc 1528.75 1332.23
13 Wet density (10/12) gm/cc 2.200 2.220
14 Dry density (13/(Avg. moisture content+1)) gm/cc 2.080 2.060
MOISTURE CONTENT
Can no. B6 B7 B4 B3
15 Wt. of can + wet soil gm 88.60 93.94 79.45 78.30
16 Wt. of can + dry soil gm 84.30 90.53 75.02 74.24
17 Wt. of water (17-18) gm 4.30 3.41 4.20 4.06
18 Wt. of can gm 20.11 20.37 21.56 21.36
19 Wt. of dry soil (18-20) gm 64.19 70.16 53.69 52.88
20 Moisture Content (19/21*100) % 6.70 4.86 7.82 7.68
21 Avg. Moisture Content % 5.78 7.75

Table 52: Summary of Result of Field Density Test of compacted soil of powerhouse from
EL 1747 to 1749.80m

Test No. Moisture Content (%) Density(gm/cc) Relative Compaction (%)

OMC Field Field MDD Field Specified
1 6.80 5.78 2.080 2.139 97.24 95
2 6.80 7.75 2.060 2.139 96.32 95

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CHAPTER 5

OFFICE WORK

5.1. Introduction
For the remaining two weeks of our internship, we were mainly focusing on carrying out the
office work. We performed the following activities in the office,

 Detail Project Report (DPR) Studying

 Technical Specification Studying
 Quantity Workout
 Bar Bending Schedule
 Preparation of Topographic Map
 Design of Drainage System
 Catchment Area Calculation
 Hydrological Study(WECS, MIP and CAR method)
 Estimation

5.1.1. Detail Project Report (DPR) Study

Feasibility report contains sufficient detailed information. Form the study of the pre-
feasibility or feasibility report that approval is made by the project owner (an individual or a
project director of the company) for the investment on the project or for a request to prepare
the DPR.
Detailed project report is prepared for the investment decision-making approval, but also
execution of the project and also preparation of the plan. Detailed project report is a complete
document for investment decision-making, approval, planning. Detailed project report is base
document for planning the project and implementing the project.

5.1.1.1. Objective of DPR

The objectives in preparation of the DPR should ensure that:

 The report should meet the questions raised during the project appraisals, i.e. the
various types of analyses should also be taken care.
 Report should be with sufficient details to indicate the possible fate of the project
when implemented.
 To understand importance of optimization of the schemes, detailed cost estimate,
payback period and return on investment.
 The report should assure performance for reliable quality with in optimum cost.

5.1.1.2. Contents in DPR

 Title page, Name, affiliation, date etc
 Acknowledgement
 Content list
 Abbreviation

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 Executive Summary
 Introduction Background
 Main technical and financial analysis
 Recommended action plan
 Appendices

5.1.1.3. Importance of DPR

 Shows project feasibility form all expects.
 Shows final cost details and benefits expected
 Detailed specification of equipment and materials
 All information to prepare tender documents
 Probable list of equipment and material manufacturers
 Project management process

5.1.2. Technical Specification Study

Specifications are the instructions, meant to supplement the drawings and provide technical
requirement of the work. The drawings along with the specification will give the complete
requirement of the structure.
Specification can be defined as an explicit set of requirements to be satisfied by a, designs,
materials, products, or services.

Technical Specification is developed for a particular construction which specifies the quality
of the final product, production process, the inspection and tests methods, which should be
conducted during construction. The technical specification is of the following types

(a) Specification for conformance: It specifies about materials, their constituents,

ingredients and workmanship. Method of testing of every material for Acceptance
Test as per NS/ IS standards is also mentioned in this specification.

(b) Specification for the performance: This part specifies quality and performance
the end product. Method of testing as per NS or IS are also mentioned

(c) Measurement and payment: Method of measurement, units of measurement and

payment is mentioned in this specification

(d) Safety, Public health Requirement: Safety and public health and environment
protection if needed are also mentioned.

5.1.2.1. Principle of writing Technical Specification

Specification writing is a very specialized and important job. Specification writing starts with
Defining the need (as what, how much, how big, where and when?), Availability of the
materials in the market (available or to be imported). Specification should also contain
Terminology, Table of contents, definitions and abbreviations to clarify the meaning of
specification. Generally specification is written in following order.

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 Scope
o Scope of specification as what a particular specification covers.
 Definition
o Definitions of the works, materials for which specifications are written.
 Description of materials
o The quantity and quality of each material/ constituent required should be
clearly mentioned. For examples for Concreted Works, Cements, Sand, (fine
aggregate), Coarse Aggregate, water and formwork etc
o Quality testing for (acceptance of materials as per accepted code) for each
material like Cement, Sand (sieve analysis) and Aggregates (e.g. Grading
Requirements in accordance with IS 2386 Part 1, Flakiness index, Water
Absorption Test as set out in IS: 2386 Part 3., Los Angeles Abrasion (LAA)
tested in accordance with IS: 2386 Part 4, Aggregate Crushing Value (ACV)
in accordance with IS: 2486 Part 4) are should also be mentioned. Similarly
Compliance Testing/Process Control Testing is also mentioned.
o The quality of equipments to be used must be specified
 Workmanship
o Transportation and storage of materials
o Method of mixing proportions / fabricating/ Erecting etc.
o Method of laying/ preparation of surface
o Compaction, finishing / curing,/ welding / painting etc. should be clearly
mentioned
 Quality Control of production
 Methods of measurement and payment
o For particularly new materials or works etc the methods of measurement and
the payment is also specified.
o If needed, tolerance for product measurement is also mentioned.
 Equipments
o The equipment, tools and plant along with their capacities and performance
should be described clearly to carry out the work.
o The method of operation also should be stated in the specification.

5.1.2.2. Proper writing of specification

 Specification must of legible (=easily readable).The sentence should be brief, direct,
simple, clear and concise without any exaggeration
 The writing style and tense should be kept same throughout.
 There should not have any grammatical mistake
 The omission or misplacement of comma, full stop etc, should not change the
meaning.
 There should not be any ambiguity in the sentence.

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 If the performance of the works required is the same as that of standard specification,
we should make it our project specific by simply mentioning the clause of the
Standard Specification. (i.e. No need of rewriting whole description)
 Should be Fair to all parties.
 Hazards/ Risks/ Safety Requirements should be specified properly.
 Specification is a part of contract which become a legal document (when contract is
signed, so they should be prepared keeping in mind constitution, prevailing Acts and
Regulations in mind.

5.1.2.3. Importance of Technical Specification

 It provides clear instructions on the intent, performance and construction of the
project.
 It can reference the quality and standards which should be applied.
 Materials and manufacturers’ products can be clearly defined.
 The requirements for installation, testing and handover can be identified.
 It can be used to support the costing of a project: not only the materials and products
but also the performance and workmanship
 The specification forms part of the contractual documents, along with the drawings,
and therefore can help minimize project risk and provide support should there be any
legal disputes.
 It supports the interpretation of the client brief and gives the client assurance that the
asset which they commissioned is being delivered.
 By being clear and concise and containing all the information, it saves the project
team, the client and the contractor time and money by providing answers to many of
the on-site construction questions.
 The specification should be used by all the project team throughout the construction
phase; it should be a living document and not stop being used at the design phase.
 The specification and any variations or value engineering can also be used for the
project audit trail and should form part of the handover documents.

5.1.3. Quantity Workout

Quantity workout is a computation or calculation of the quantities required and expenditure
likely to be incurred in the construction of a work.

The estimate is the probable cost of a work and is determined theoretically by mathematical
calculation based on the plans and drawing and current rates.

5.1.3.1. Excavation for tail race of SUHEP

The evaluator should look for changes in the ground surface near the tailrace for the cascade
of water coming from the tail race of SUHEP to Chillimi HEP. A variety of factors could
cause these changes. 1st of all demolition of existing wall of Chilime HEP was proposed to be
done. Then the excavation and filling process takes place. For this process

5.1.4. Bar Bending Schedule

Bar bending schedule is used to communicate the design requirement if reinforcement steel to
the fabricator and execution team and to enumerate the weight of each size of steel. This is a

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list of reinforcement bars in a tabular form and the following essential details are generally
given for a bar bending schedule in RCC works:

1. Bar mark-this gives the position of the bar in the structure

2. Diameter of bar
3. The shape and bending dimensions of the bar.
4. Length of each bar
5. Number of the same type of bars
6. Total length
7. Weight of each bar per meter length
8. Total weight.

5.1.4.1. Importance of Preparing Bar Bending Schedule

 For a structural engineer, concrete reinforcement is very critical and time consuming
job. Steel reinforcements are generally used in the form of circular bars in a concrete
structure.
 They resemble a skeleton in human body. Only concrete without any reinforcement is
capable to withstand compression but cannot resist tension.
 Steel is one of the widely used reinforcements to strengthen the concrete and bear
dead and live loads. Bar-bending-schedule is the schedule of steel bars reinforcement
prepared well before cutting and bending rebar.
 Bar bending schedule helps in determining appropriate material quantities, strength
and cost estimation.

5.1.4.2. General guidelines to be followed in preparing BBS

 The bars should be grouped together for each structural unit, e.g. beam, column, etc.
 For cutting and bending purposes schedules should be provided as separate A4 sheets
and not as part of the detailed reinforcement drawings.
 The form of bar and fabric schedule and the shapes of bar used should be in
accordance with BS 8666.
 It is preferable that bars should be listed in the schedule in numerical order.
 It is essential that the bar mark reference on the label attached to a bundle of bars
refers uniquely to a particular group or set of bars of defined length, size, shape and
type used on the job.
 This is imperative as a bar mark reference can then point to a class of bar
characteristics. Also, this helps steel fixers and laborers keep track of the type and
number of bars needed to complete a certain work

5.1.4.3. Bar Bending Schedule User

 Detailer
 person checking the drawing
 contractor who orders the reinforcement
 organization responsible for fabricating the reinforcement
 steel fixer

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 the quantity surveyor

Quantity surveyor is responsible for estimation and costing operations of a project. This kind
of surveying demands a high level of precision. Bar Bending Schedule helps the quantity
surveyor to consolidate the number of bars required of each bar type.

This leads to an estimation of the quantity of steel, which translates to the cost requirements
for steel work. Hence, BBS is used by the contractor who orders the reinforcements as well.
Unit cost of steel is charged by weight of steel purchased.

5.1.5. Preparation of Topographic Map

5.1.5.1. Introduction
A topographic map is a two-dimensional representation of a three-dimensional land surface.
Topographic maps are differentiated from other maps in that they show both the horizontal
and vertical positions of the terrain.

Through a combination of contour lines, colors, symbols, labels, and other graphical
representations, topographic maps portray the shapes and locations of mountains, forests,
rivers, lakes, cities, roads, bridges, and many other natural and man-made features. They also
contain valuable reference information for surveyors and map makers, including bench
marks, base lines and meridians, and magnetic declinations.

Topographic maps are used by civil engineers, environmental managers, and urban planners,
as well as by outdoor enthusiasts, emergency services agencies, and historians.

5.1.5.2. Procedure
The software is grouped into menus based on the similarity of functions.

Table 53: Summary of the menu are provided

S.N. Menu Description

Contains functions for manipulating points (Add, Import, Export,
1 Points
Delete, Interpolate & Process points)
2 Draw Allows inserting blocks & drawing of features and boundaries.
Functions for triangle related tasks (Triangulation, drawing and
3 Triangles
erasing triangles)
4 Contour Menus for drawing, erasing and annotating of contours.
5 Alignment Menus for drawing, manipulating and extracting alignments.
6 X-Section Menus for extracting and drawing L-Profile and Cross Section.
Provides miscellaneous utilities for polyline conversion, switching
7 Utilities
active AutoCAD document and exporting DTM file.
8 Help About the software

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5.5.3. Plotting the Sample Points

In order to plot the points contained in the file Points.csv in AutoCAD, follow the steps
below.
1. Select menu Points->Import Points from File. A dialog box will appear.
2. Click the Import Points button.
3. Select the Points.csv file. The file is located in the Samples folder in the SW_DTM
installation folder.

5.5.4. Drawing Contours and Cross Sections

For drawing contours and cross sections, we will be using the Small_Sample.dwgdrawing
file. The file already contains the points in the Points.csv file, along with features and
alignments.
Follow the steps given below to draw contours in the sample drawing file.
1. Open the drawing file Small_Sample.dwgin AutoCAD.
2. Open SW_DTM, select Points->Process Points.
3. To process all points and features, select All Points and Features in the processing
options in the bottom right corner. Ensure that the layer Features is selected in the feature
layers list. Click OK to process points.
4. After processing is completed, click menu Triangles->Triangulate. A message box will
appear after triangulation is completed.
5. Click Contours->Draw Quick Contour. Set the contour interval and click Draw.
Contours will be drawn in AutoCAD.
6. Click X-Section->Sections by DTM.
7. Change mode to L-Profile and X-Section.
8. Check Write Chainageto mark chainages along the alignment.
9. Set the left and right Partial Distances.
10. Click Select. Then select a convenient location as the save file destination in the Save as
dialog box that appears.
11. Select the alignment line that is already present in the sample drawing.
12. To draw Cross sections, click X-Section->Draw X-Section. A dialog box will appear.
13. To draw all cross sections click Draw All. AutoCAD will ask you to select a reference
origin point for the drawings.

5.1.6. Design of Drainage System

Design of drainage system depends upon the shape, size, amount of water, slope, etc.

5.1.6.1. Design process according to shape of drainage

 For trapezoidal section
A trapezoid shape is sometimes used for manmade channels and the cross section of
natural stream channels are often approximated by a trapezoid area. The diagram at
the right shows a trapezoid and the parameters typically used for its shape and size in
open channel flow calculations. Those parameters, which are used to calculate the
trapezoid area and wetted perimeter, are y, the liquid depth; b, the bottom width; B the
width of the liquid surface; λ, the wetted length measured along the sloped side; and

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α, the angle of the sloped side from vertical. The side slope is usually specified as
horizontal: vertical = z: 1.
The cross sectional area of flow is the trapezoid area:
A = y(b + B)/2, or
A = (y/2)(b + b + 2zy), because B = b + 2zy, as can be seen from the diagram.

Figure: Trapezoidal Cross Section

Simplifying, the trapezoid area is: A = by + zy2.

The wetted perimeter is: P = b + 2λ,
But by Pythagoras Theorem:
λ2 = y2 + (yz)2, or λ = [y2 + (yz)2]1/2,
So the wetted perimeter is:
P = b + 2y(1 + z2)1/2,and
The hydraulic radius for a trapezoid is:
RH = (by + zy2)/[b + 2y(1 + z2)1/2]

 For rectangular section

The simplest open channel flow cross section for calculation of hydraulic radius is a
rectangle. The depth of flow is often represented by the symbol, y, and b is often used
for the channel bottom width, as shown in the diagram at the left. From the hydraulic
radius definition: RH = A/P, where A is the cross sectional area of flow and P is its
wetted perimeter. From the diagram it is clear that A = by and P = 2y + b, so the
hydraulic radius is: RH = by/(2y + b) for an open channel flow through a rectangular
cross section.

Figure: Rectangular Section

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5.1.7. Catchment Area Calculation

A topographic map is a two-dimensional representation of a three-dimensional land surface.
Topographic maps are differentiated from other maps in that they show both the horizontal
and vertical positions of the terrain.
Through a combination of contour lines, colors, symbols, labels, and other graphical
representations, topographic maps portray the shapes and locations of mountains, forests,
rivers, lakes, cities, roads, bridges, and many other natural and man-made features. They also
contain valuable reference information for surveyors and map makers, including bench
marks, base lines and meridians, and magnetic declinations.
Topographic maps are used by civil engineers, environmental managers, and urban planners,
as well as by outdoor enthusiasts, emergency services agencies, and historians.

5.1.8. Hydrological Study

5.1.8.1. WECS/DHM method
It is a modification of WECS approach of1982 and has been developed jointly byWECS and
DHM in cooperation with WMO(World Meteorological Organization),WERDP (Water and
Energy ResourceDevelopment Project, until 1989) andWISP (WECS/NEA Institutional
SupportProgramme) in 1990. It treats the entirecountry as a single hydrological region.
Theregionalization was done for low flows, longterm flows and flood flows.

5.1.8.2. MIP (Medium Irrigation Project) Method

It was developed in 1982 by Sir M. Mac Donaldand Partners Limited in association with
Hunting Technical Services Limited in which Nepal is divided into 7 hydrological regions.
No regionalization were done for either low flows or flood flows. It can onlygive the mean
monthly flows.

These two methods are in use for the estimation ofthe flow conditions for various medium-
small scal ewater resource projects at the ungauged locations. When WECS/DHM method
was developed, thecountry had only 54 hydrological stations whichwere insufficient to
completely represent thecountry in terms of hydrological regime. So it has made several
recommendations of updating themethod every five years, developing hydrometricnetwork
review and plans, making extensiveprecipitation study including the Himalayan region and
Siwaliks etc.

WECS/DHM has inferred the MIP method asless comprehensive study. This design manual
is intended for guidance only and consequently it is not as complete, nor as rigorous, as
theWECS (1982) study (WECS/DHM, 1990). The hydrograph developed should be checked
orupdated so that the prediction made on the basisof the hydrograph is accurate and the
dischargepredicted could be used.

But these recommendations have not been realized and the method is in use since they are
developed. Since there is no other choice for the ungauged locations; these methods are
widely relied upon by the water resource projects. As these tools didn’t meet the
recommendations, it isnot wise to fully depend upon their predictions. So this study is to

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check the anomaly andreliability so that the risk associated with theirpredictions will be
timely avoided.

 For instantaneous flood, formula for 2 year return period is:

Q2 = 1.8767 × (area of basin below 3000m+1)0.8783

 Formula for 100 year return period is:

Q100 = 14.63 × (area of basin below 3000m +1)0.7342
Based on the algebraic evaluations of the equations used for lognormal distribution, the
following relationships (WECS/DHM. 1990) can be used to estimate floods at other return
periods.
𝐐𝐓=𝐞𝐱𝐩 (𝐥𝐧𝐐𝟐+𝐬Ϭ)
where, S is the standard normal variant, Ϭ is the parameter which is computed as

Ϭ =ln (𝐐𝟏𝟎𝟎/𝐐𝟐)/2.326
where, S is the standard normal variant.

Table 54: Value of Standard Normal Variant for Corresponding Return Period

Standard
Return
Normal
Period T
Variant
(yrs)
(ϭ)
2 0
5 0.842
10 1.282
20 1.645
50 2.054
100 2.326
200 2.576
500 2.876
1000 3.09
5000 3.54
10000 3.719

5.1.8.3. CAR (Catchment Area Ratio) Method

Historically, flow rates in ungaged catchments have been estimated using a variety of
techniques. Perhaps the earliest and most common technique for estimating daily flow in an
ungaged catchment is the catchment (watershed) area ratio method. The area ratio method is
used to estimate flow in an ungaged catchment when a nearby gaged watershed is present for
use as a reference. The method estimates flow at an ungaged location by multiplying the
measured flow at the nearby reference gage by the area ratio of the ungaged to gaged
watersheds
Qb= Qi × Ab/Ai
Where,
Q = Discharge in m3/s
A= drainage area in sq. km.

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Suffix ‘b’ stand for base station (ungauged station) and ‘i’ stands for index station (gauged
station).
Advantages

 This method is useful if the hydro-meteorological data of the index station having
similar catchment characteristics with the base station are available for the data
extension.
 Easy to excess the data.
 Mostly preferable

5.1.9. Preparation of Bill of Quantity (BOQ) and Rate Analysis

5.1.9.1 Bill of quantities (BOQ)
Bill of quantities (BOQ) is a document used in tendering in the construction industry /
supplies in which materials, parts, and labor (and their costs) are itemized.

Purpose:
 To enable all contractors tendering for a contract to price on exactly the same
information. Subsequent to this, it is widely used for post-tender work such as:
material scheduling; construction planning; cost analysis; and cost planning.

Importance of BOQ
 It provides basic idea of the project by giving the quantities to tenderers.
 It defines the extent of the work. (But it should be identified in line with drawings&
specification as well).
 It gives estimated or anticipated contract sum. (very important to client)
 It provides a basis for valuation of variation. (Variation is to be discussed in detail).

Major Parts of BOQ

Parts of BOQ can be varied according to the project size as well the practices. Generally it
has measured works, Preliminaries & Provisional sums. The contract sum would be addition
of these three items.

5.1.9.2. Rate analysis:

In order to determine the rate of a particular item, the factors affecting the rate of that item
are studied carefully and then finally a rate is decided for that item. This process of
determining the rates of an item is termed as analysis of rates or rate analysis.

The rate of particular item of work depends on the following:

 Specifications of works and material about their quality, proportion and constructional
operation method.
 Quantity of materials and their costs.
 Cost of labors and their wages.
 Location of site of work and the distances from source and conveyance charges.
 Overhead and establishment charges
 Profit

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Purpose of Analysis of rates:

 To work out the actual cost of per unit of the items.
 To work out the economical use of materials and processes in completing the
particulars item.
 To work out the cost of extra items which are not provided in the contract bond, but
are to be done as per the directions of the department.
 To revise the schedule of rates due to increase in the cost of material and labor or due
to change in technique.

5.1.10 Flood frequency analysis

Flood frequency analysis is used to predict the design floods for sites along a river. The
technique involves using observed annual peak flow discharge data to calculate statistical
information such as mean values, standard deviations, skewness, and recurrence intervals.
The following methods can be used for flood frequency analysis.

5.1.10.1 Gumbel’s distribution

Gumbel’s deviation probability distribution is widely used for extreme value analysis of
hydrologic and meteorological data like floods, maximum rainfalls and other events. Gumbel
defined the flood as the largest value of 365 daily flows, and annual series constitute a series
of largest values of flow.(Subramanya, 2013)

XT = x + K × 𝛛 (𝐧−𝟏) ……… i
Where, 𝛛 (𝐧−𝟏) = standard deviation of sample of size

2
∑ (X −x)
¿√
N−1

yt − yn
K= ………….. ii
Sn
Where, yt is reduced variant for given time T
yn is reduced mean and Sn is reduced the standard deviation

Table 1Reduced mean yn in Gumbel's Extreme Value

N 0 1 2 3 4 5 6 7 8 9

10 0.4952 0.4996 0.5035 0.5070 0.5100 0.5128 0.5157 0.5181 0.5202 0.5220

20 0.5236 0.5252 0.5268 0.5283 0.5296 0.5309 0.5320 0.5332 0.5343 0.5353

30 0.5362 0.5371 0.5380 0.5388 0.5396 0.5402 0.5410 0.5418 0.5424 0.5430

40 0.5436 0.5442 0.5448 0.5453 0.5458 0.5463 0.5468 0.5473 0.5477 0.5481

50 0.5485 0.5489 0.5493 0.5497 0.5501 0.5504 0.5508 0.5511 0.5515 0.5518

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60 0.5521 0.5524 0.5527 0.5530 0.5533 0.5535 0.5538 0.5540 0.5543 0.5545

70 0.5548 0.5550 0.5552 0.5555 0.5557 0.5559 0.5561 0.5563 0.5565 0.5567

80 0.5569 0.5570 0.5572 0.5574 0.5576 0.5578 0.5580 0.5581 0.5583 0.5585

90 0.5586 0.5587 0.5589 0.5591 0.5592 0.5593 0.5595 0.5596 0.5598 0.5599

DistributionN = Sample size

Table 2Reduced Standard deviation Snin Gumbel's Extreme Value Distribution

N 0 1 2 3 4 5 6 7 8 9

10 0.9496 0.9676 0.9833 0.9971 1.0095 1.0206 1.0316 1.0411 1.0493 1.0565

20 1.0628 1.0696 1.0754 1.0811 1.0864 1.0915 1.0961 1.1004 1.1047 1.1086

30 1.1124 1.1159 1.1193 1.1226 1.1255 1.1285 1.1313 1.1339 1.1363 1.1388

40 1.1413 1.1436 1.1458 1.1480 1.1499 1.1519 1.1538 1.1557 1.1574 1.1590

50 1.1607 1.1623 1.1638 1.1658 1.1667 1.1681 1.1696 1.1708 1.1721 1.1734

60 1.1747 1.1759 1.1770 1.1782 1.1793 1.1803 1.1814 1.1824 1.1834 1.1844

70 1.1854 1.1863 1.1873 1.1881 1.1890 1.1898 1.1906 1.1915 1.1923 1.1930

80 1.1938 1.1945 1.1953 1.1959 1.1967 1.1973 1.1980 1.1987 1.1994 1.2001

90 1.2007 1.2013 1.2020 1.2026 1.2032 1.2038 1.2044 1.2049 1.2055 1.2060

100 1.2065

N = Sample size

The value of yt can be calculated as:

Yt =−¿ ……………. iii

5.1.10.2 Log Pearson type III distribution

The log transferred series with base 10 are assumed to follow Log Pearson type III
distribution and then analyzed. If x is the variant of a random hydrologic series, the Z variant
is given by:

Z=log x ……………………………………………………. i

For this series, for any recurrence interval T

ZT =Z+ K Z σ Z………………………………………………. ii

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where, KZ= frequency factor, function of T and CS

Cs is the coefficient of skewness.

T is the return period in the year

Source:(Subramanya, 2013)

Table 3Kz = F (Cs, T) for use in Log Pearson type III Distribution

Coefficient of Recurrence interval T in years

skewness, Cs 2 10 25 50 100 200 1000

3.2 -0.396 1.18 2.278 3.152 4.051 4.97 7.25

2.5 -0.36 1.25 2.262 3.048 3.845 4.652 6.6

2.2 -0.33 1.284 2.24 2.97 3.705 4.444 6.2

2 -0.307 1.302 2.219 2.912 3.605 4.298 5.91

1.8 -0.282 1.318 2.193 2.848 3.499 4.147 5.66

1.6 -0.254 1.329 2.163 2.78 3.388 3.99 5.39

1.4 -0.225 1.337 2.128 2.706 3.271 3.828 5.11

1.2 -0.195 1.34 2.087 2.626 3.149 3.661 4.82

1 -0.164 1.34 2.043 2.542 3.022 3.489 4.54

0.9 -0.148 1.339 2.018 2.498 2.957 3.401 4.395

0.8 -0.132 1.336 1.998 2.453 2.891 3.312 4.25

0.7 -0.116 1.333 1.967 2.407 2.824 3.223 4.105

0.6 -0.099 1.328 1.939 2.359 2.755 3.132 3.96

0.5 -0.083 1.323 1.91 2.311 2.686 3.041 3.815

0.4 -0.066 1.317 1.88 2.261 2.615 2.949 3.67

0.3 -0.05 1.309 1.849 2.211 2.544 2.856 3.525

0.2 -0.033 1.301 1.818 2.159 2.472 2.763 3.38

0.1 -0.017 1.292 1.785 2.107 2.4 2.67 3.235

0 0 1.282 1.751 2.054 2.326 2.576 3.09

-0.1 0.017 1.207 1.716 2 2.252 2.482 2.95

-0.2 0.033 1.258 1.68 1.945 2.178 2.388 2.81

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-0.3 0.05 1.245 1.643 1.89 2.104 2.294 2.675

-0.4 0.066 1.231 1.606 1.834 2.029 2.201 2.54

-0.5 0.083 1.216 1.567 1.777 1.955 2.108 2.4

-0.6 0.099 1.2 1.528 1.72 1.88 2.016 2.275

Coefficient Recurrence interval T in years

of skewness,
Cs 2 10 25 50 100 200 1000

-0.7 0.116 1.183 1.488 1.663 1.806 1.926 2.15

-0.8 0.132 1.166 1.448 1.606 1.733 1.837 2.035

-0.9 0.148 1.147 1.407 1.549 1.66 1.749 1.91

-1 0.164 1.128 1.366 1.492 1.588 1.664 1.88

-1.4 0.225 1.041 1.198 1.27 1.318 1.351 1.465

-1.8 0.282 0.945 1.035 1.069 1.087 1.097 1.13

-2.2 0.33 0.844 0.888 0.9 0.905 0.907 0.91

-3 0.396 0.66 0.666 0.666 0.667 0.667 0.668

2
√ ∑ (Z−z)
σ Z= …….……. iii
N −1
3
N ∑(Z−z)
C S= ……….... iv
(N−1)(N−2)σ Z 3

where, N = sample size

Z = mean of Z values
XT = antilog (ZT)
XT is the required flood for the corresponding return period.

5.1.10.3 Log normal distribution

In this distribution, logarithmic values of sample data are assumed to follow a normal
distribution. The distribution is same as log Pearson type when CS=0.

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CHAPTER 6

FIELD VISIT

During the internship period, we had the opportunity to visit another under construction
hydropower located nearby Rasuwagadhi Hydroelectric Project (111 MW)

6.1. Introduction
Rasuwagadhi Hydroelectric Project is a run of the river type project with the design discharge
of 80 m3/sec and available gross head of 168m. The source river is BhoteKoshi (Trishuli)
which flows down from Tibet, China entering Nepal at Rasuwagadhi reaches down to
Trishuli in Rasuwa District. The headworks site is located about four hundred meters
downstream from the confluence of Kerungkhola and Lendekhola which are the Boundary
Rivers of Nepal and China (Tibet).

6.2. Salient Features

Project Details
Project Name : Rasuwagadhi Hydropower Project
Development Region : Central Development Region
District : Rasuwa
Location of Project Site : Timure and Thuman VDC
Water Source : Bhotekoshi
Type of Scheme : RoR
Access Road : Existing Road‐Kalanki‐Galchi-Timure
Installed Capacity : 111 MW
Gross head : 168 m
Rated Design head : 158.6 m
Design Discharge : 80 cumecs
Annual Energy Generation : 613.875 GWh

Hydrology
Catchment Area : 3300 sq km
Average Precipitation : 2211 mm/year
100 years Design Flood : 1167 cumecs
Design Discharge : 80 cumecs

Headworks
Diversion structure : Non-gated weir
Length of weir : 61.5 m
Weir crest elevation : EL 1790.00msl
Height of weir :10 m
Under sluice : Two Radial Sluice gate along with stop log gate

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Crest of Sluice : EL 1782.50 msl

Size of Sluice gates (bxh) : 6.5 m x 5 m
Intake Type : Side off Intake
Size of opening : 9 x 5 ‐ 3 nos
Intake Invert Level : EL 1785.50msl

Gravel Trap
Type : Rectangular
Particle Size to be settled : 2 mm
Length of Gravel Trap : 26.2 m length
Bed Slope : 1:50

Desander
Type : Underground Serpent Sediment Slucing System
No of Basin : 3 Nos
Particle Size to be settled : 0.2 mm
Length of Desander (Main Part) : 125m
Length of Transition : 34.36m
Size of Desander Cavern : 15m * 15.38m
Size of Desander (Width X Depth) : 15m * 17.1m
Bed Slope : 1:40

Headrace Tunnel
Conveyance Length : 4184.5m
Type : Horseshoe shaped tunnel
Internal Diameter : 7.150m * 5.162m (Class I, II and III)
: 3m diameter lining (Class IV, V and V’a’)
Average tunnel slope : 0.005409

Surge Tank
Type : Underground, restricted orifice
Size : 16m diameter and 59.15m height
Max. Upsurge EL : 1806.00 msl
FSL. EL : 1790.00 msl
Max. Downsurge EL : 1765.00 msl

Penstock Pipe
Type : Steel lined Underground penstock
 Vertical Penstock Shaft:
Height without bend : 114m
Height with bend : 139.05m
Size of Pipe : 4.8m
 Horizontal Penstock Pipe:

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Length : 127.307m
Pipe Material : Mild steel
Size of Pipe : 4.8m-12.5m, 4m-14.895m, 2.9m-17.276m, 2m- 79.236m
Number of supports : 5 Nos Saddle Supports

Powerhouse Cavern
Type : Underground with outdoor Switchyard
PH Cavern dimension (l x b) : 76.3 m x 15m
Height of PH Cavern : 39.5m

Transformer Cavern
Type : Underground
Cavern dimension (l x b) : 85.7m x 12.9m
Height of Transformer Cavern : 16.1m

Tailrace Tunnel
Type : Horseshoe shape
Internal Diameter : 6m
Length : 598.55 m
Tailrace water level : EL 1615.0msl

Turbine
Number of Units :3
Type of Turbine : Francis
Shaft Arrangement : Vertical
Rated discharge for each turbine : 26.67 m3/s
Rated Head : 158.6 m
Rated Output for each unit : 37000 kW
Turbine Axis Level : 1615.2 msl
Machine Floor Level : 1625.0 msl

Generators
No of units :3
Generator Type : 3 phase AC Synchronous, 50Hz
Excitation : Brushless excitation
Layout : Vertical
Rated Output : 43.75 MVA

Transmission Line
Transmission Length : 10 km (Rasuwagadhi PH – Chilime S/S)
Transmission Voltage : 132 kV
Type of Circuit : Double circuit line
Proposed Interconnection Point : NEA 132/33 kV Proposed Substation at Switiatar

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Power and Energy

Installed Capacity : 111 MW
Deemed Energy : 613.875 GWh
Dry Season Energy : 84.318 GWh
Wet Season Energy : 529.557 GWh

Construction Period : 4 years

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CONCLUSION

In conclusion, this internship which has been included in our course has been very beneficial
to us. We have learnt a lot during our internship period about the construction of a
Hydropower project and also the office work carried out during the construction period of
Hydropower project. We believe that the objectives of the internship activity have been met
by us during the 6 weeks spent under the Host Organization.

Some of the problems that we encountered during our internship period were:

1. Entering the HRT and Audit 1 required gum boots, however we could not provided
with gum boots due to the reason that extra gum boots were not present
2. The vehicles present in the site tended to be broken down thus transportation was a
problem

Some of the problems that we were visible during our 4 week site stay are listed below:

1. Works were not carried out on the exact time according to the schedule provided by
the Contractor; there was always a delay of some sort.
2. Communication gaps could be seen between some cases; as during rib installation in
Audit I, number of tie rods and anchor rods were less than required though instruction
had been provided by the supervising engineer to the workers, another example of
such communication gap could be seen during rock bolt pull out test in surge shaft,
instructions had been given for concrete padding to be done on the marked rock bolts
however it had not been carried out as there had been a change in contractors from
Himal Hydro to Tundi constructions, thus the information had not been clearly
transferred.

Finally in conclusion, as a whole this internship period was very beneficial for us. We have
been able to experience the construction activities that occur in development of a
Hydropower project plus the office work that goes on to make it all possible.

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REFERENCES

 Baral, S. (2013). Fundamentals of Hydropower Engineering. Kathmandu: Engineering

and Education services Pvt. Ltd.
 The Constructor. (2017). Preparation of Bar Bending Schedule and its advantages.
Retrieved from theconstructor.org: theconstructor.org/practical-guide/preparation-of-bar-
bendingschedule/7629/
 Karki, B., Karki S., Shrestha R. (2018). Report on Internship Activity Sanjen Hydro
Electric Project (42.5MW). Dhulikhel: Kathmandu University
 Baniya R., Bhandari B., Gautam S., Khadka P. (2018). Report on Internship Activity
Maya Khola Hydroelectric Project. Dhulikhel: Kathmandu University
 Khadka, S.S. (2018). Drill and Method in Tunneling, Lecture notes[PDF]
 Ákos T.(2015). Tunneling and Underground Construction Technology [PDF]. Retrieved
from https://se.sze.hu/images/ngm_se108_1/Tunnels_2015-03-20_Toth_1-Excavation.pdf
 Subramanya, K. (2013). Engineering Hydrology. New Delhi: McGraw Hill Education
Pvt. Ltd.

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ANNEXES

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ANNEX I

DETAIL DRAWINGS

General Plan of the Project

General Plan of the Project

Annex I-1
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Plan and Profile of HRT from headwork to chainage (1+100)m

Plan and Profile of HRT chainage (1+100)m to (2+500)m

AnnexI-2
INTERNSHIP REPORT AT SANJEN HEP 2019

Plan and Profile of HRT chainage (2+500)m to start of penstock tunnel

Section of Rock Trap

AnnexI-3
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Plan and Section of Surge Tank

Rock Support Design of Surge Tank

AnnexI-4
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Plan and Section of Valve Chamber

Plan and Section of Penstock Tunnel

AnnexI-5
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Plan and Section of Surface Penstock

Rock Support Design of HRT

AnnexI-6
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Rock Support Design of Penstock Tunnel

Rock Support Design of Penstock Tunnel (Inclined)

AnnexI-7
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Plan of Sanjen HEP Powerhouse

Section of SHEP Powerhouse

AnnexI-8
 INTERNSHIP REPORT AT SANJEN HEP 2019

ANNEX II

DETAILS OF OFFICE WORK

The details of the office work is being attached along with this. This section mainly includes
the computation carried on MS Excel Worksheet and AutoCAD drawing of following works.

 Hydrological Study (WECS/ DHM and MIP method)

 Preparation of Topo Map using SWDTM
 Preparing Cross and Longitudinal Section of desired alignment of access road
drainage
 Excavation Workout
 Quantity Workout
 Bar Bending Schedule
 Rate Analysis
 Catchment Area Calculation
 Estimation

Annex II-1
 INTERNSHIP REPORT AT SANJEN HEP 2019

ANNEX III

WEEKLY INTERNSHIP ACTIVITIES

The final year internship to fulfill the undergraduate course started on 8th May, 2019.
First Week: (8th May, 2019 – 13th May, 2019)
Day 1:
 Power house visit (Sanjen HEP) and Sanjen Upper HEP head works and power
house visit.
 Observed compaction of soil to 2B grade for foundation for surface structures.
 Field Density Test of the compacted soil by Sand Replacement Method for which
design Maximum dry density (MDD) of 2.139gm/cc and OMC of 95% and the
observed values were MDD of 2.090 gm/cc and OMC of 97.68%.
 Observed compressive Strength test of powerhouse shear wall concrete ( C 25/30 )
whose 28 days strength was found to be 39.19 N/mm2.
 Inspection of no. and size of rebar for mass concreting.
Day 2:
 Slump test performed on site for the concrete, to be used in concreting of powerhouse,
whose slump height was observed 135mm.
 Mass concreting of the powerhouse upto the depth of 1.3m (1743.40m – 1744.70m)
in the bifurcation area which covered the volume of 200 m3.
Day 3:
 Site visit of Sanjen Upper HEP headrace tunnel, adits and surge shaft.
 Desk study of headrace tunnel and powerhouse of Sanjen Upper HEP.
 Observed chipping of the concrete in bifurcation area
Day 4:
 Curing and chipping of concrete in powerhouse bifurcation area and shear wall.
 7 day Compressive strength test of concrete of spillway found to be 23.77 N/mm2.
Day 5:
 Site visit to Adit III and Penstock Tunnel of Sanjen HEP and surge shaft observation.
 Rebar Laying in powerhouse.
 Blasting at Adit I.
Day 6:
 Visit HRT inlet
 Observe Tunnel Cycle in audit I (Drilling, Charging, Blasting and Mucking)
 Observe rebar laying and formwork at bifurcation area.

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Second Week: (14th May, 2019 – 19th May, 2019)

Day 1:
 Observe head works of Sanjen HEP.
 Rebar laying in headworks.
 Trash rack and gate fixing.
Day 2:
 Observe batching plant of Sanjen Upper HEP.
 Slump test (100-150mm slump height ) was found out to be 140mm.
 Observe concreting in EDV area of Sanjen Upper HEP power house.
 Observe Tunnel cycle (Drilling and Charging only) due to the unsafe tunnel
condition.
 Learn about loading, charging, drilling materials, face of tunnel.
Day 3:
 Observe the failure of tunnel (Adit-1) due to weak zone
 Shotcrete on erode surface before rib installation for support.
 Mass concreting of powerhouse for 0.8m depth ( 1744.70m – 1745.50m ) covering
volume of 90 m3 for which C25/30 concrete was used.
Day 4:
 Production of aggregate at crusher site, sand washing and production of sand.
 7 day cube test of Adit III of concrete C28/35 whose strength was 18.67 N/mm2.
Day 5:
 Chipping, curing, formwork placement, rebar laying for shear wall
 Filling and compaction in power house.( Soil used from tunnel after mucking)
Day 6:
 Field Density Test of the compacted soil at powerhouse whose MDD and OMC were
found out to be 2.070 gm/cc and 96.78% respectively.
 Observe footing construction for transmission tower.

Third Week: (20th May, 2019 –25th May, 2019 )

Day 1:
 Visit headworks of Sanjen HEP.
 Shotcreting in head race tunnel.
 Inspection of rebar laying in power house.
Day 2:
 Perform slump test.( 100-150mm slump height ) whose slump height was 110mm.
 Mass Concreting of 90 m3 on powerhouse bifurcation area with depth 1.2m
(1745.50m – 1746.70m)

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Day 3:
 Inspection in surge shaft ( Adit III ) where the padding in the marked rock bolt were
not done properly due to which targeted rock bolt pull out test could not be
performed.
Day 4:
 Rib support installation in Adit I
 Inspection of cavity in tunnel face in Adit I was done and additional spilling dowels
and rib support were deemed necessary.
 Required quantity of backfill concrete for the cavity seemed high.
 Learn Bar Bending Schedule.
Day 5:
 Curing, rebar laying at powerhouse.
 Inspection of rib support installation at Adit I where steel plate laying and no. of rods
for rib support were checked.
 Surveying for change of control point for estimation of backfill concrete quantity.
 Observe trial mix of concrete for powerhouse.
 Slump test of the trial mix (50-100 mm to be obtained) was observed to be 70 mm.
 Observe compressive strength of TM-90 (30 N/ mm2 to be obtained) which was found
out to be 42.80 N/mm2.
Day 6:
 Inspection of rib support installation at Adit I for concreting was done and
insufficiency in no. of tie rods and anchor rods was observed.
 Supervision of concrete mix for concrete at rib till spring line which was c12/15 in
accordance with TM-99.
 Slump Test for the prepared concrete (50-100mm slump) was 20mm and cubes were
prepared for compressive strength test.
 28 days compressive strength fibre shotcrete (35 N/ mm2 to be obtained ) was found
to be 43.67 N/mm2.

Fourth Week: (26th May, 2019 –31st May, 2019 )

Day 1:
 Visit powerhouse and observed the Alimak Method in Penstock tunnel which is used
to perform drilling, blasting, providing rock bolt support, itc in inclined surface.
 Observe sand washing and production of sand.
 Excavation for sub-surface drains laying.
 Concreting of transmission tower
 Rebar laying for slab at powerhouse.
Day 2:
 Rock bolt grouting in Adit I for whichGrout mixture in accordance to Grout mix 71 of
w/c ratio 0.37 was used and preparation of cubes for compressive strength test (5 cm3
mold) was done.

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 Observe compressive strength of TM-91 of 3 days (8 N/mm2) C16/20 which was

24.71 N/mm2.
 28 days compressive strength test of Power House Shear wall concrete C25/30 (30
N/mm2 to be obtained) was 42.55 N/mm2.
 28 days compressive strength test of Power House Shear wall concrete C25/30 (30 N/
mm2 to be obtained) was 43.64 N/mm2.
 7 days compressive strength test of Fiber Shotcrete concrete C28/35 (19.6 N/ mm2 to
be obtained) was 31.70 N/mm2.
 7 days compressive strength test of Fiber Shotcrete concrete C12/15 (8.1 N/ mm2 to
be obtained) was 16.81 N/mm2.
Day 3:
 Observe concreting in Power house slab covering 177 m3 with concrete C25/30.
 Levelling of the excavated area for the center line of the drain pipe i.e. at an elevation
of 1749.1m and laying of perforated pipe of diameter 20cm.
 Observe hydromechanical equipment such as Main Inlet Valves and Manifold to be
installed in the powerhouse.
Day 4:
 Observe sub-surface drain laying and geo-textile material to be used for wrapping the
perforated pipe.
 Observe production of aggregate at crusher site.
 Observe the progress of the transmission tower construction i.e. two legs had been
concreted and reinforcement for the other two had been done.
Day 5:
 Site visit to Rasuwagadi Hydropower Project which is discussed in Chapter 5.
Day 6:
 Return from site.

Fifth Week: (2th June- 9th June, 2019), holiday in 5th June.
Day 1:
 Detail Project Report (DRP) study
Day 2:
 Technical Specification Study
Day 3:
 Quantity Workout of SHEP tailrace.
 Estimation of quantities.
Day 4:
 Bar bending schedule of SHEP tail race.
 Literature review of bar bending schedule.
 Preparationof bar bending schedule.
Day 5:

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 Estimation of quantities such as excavation, structure cut, drain cut and back filling of
gabion protection wall for access road in SUHEP
Day 6:
 Design of side drain at access road of SHEP balancing pond.

Sixth Week: (June 10- June 16, 2019)

Day 1:
 CAD drawing design of side drainage
 Layout of drainage
 Shape, size, slope.
Day 2:
 Catchment area calculation of Chhupchung Khola.
 Preparation of topographic map
 Catchment area by GIS, Google earth, etc
Day 3:
 Hydrology analysis.
 WECS, MIP, CAR method for calculation of peak discharge.
Day 4:
 Estimation of concreting in power house.
 Study of detail drawing of power house in bifurcation area.
Day 5:
 .
Day 6:


Annex III-5