GEO TECHNICAL INVESTIGATION REPORT FOR

PROPOSED MONO TOWER 400KV TRANSMISSION LINE

FOR PSP-CPSS 400KV QMDC LINE, PD+09 TOWER AT
PINNAPURAM, KURNOOL, ANDHRA PRADESH.

Location:AP-2A/0

FOR
M/s.MEGHA ENGINEERING & INFRASTRUCTURE LTD.

Geotechnical Consultant
M/s ANJI GEO SLUTIONS
Drilling & Grouting Works Geo
Technical Investigations
#3-103,Near P.A.B.R. Dam(V),Kudair(Mdl),Anantapuram(Dist.,)
Phone: 9908023322,9866748961
Email : anjiconsultancy19@gmail.com
 TABLE OF CONTENTS
Sheet No.

1.0 INTRODUCTION 2
1.1 Project Description 2
1.2 Purposes of Study 2

2.0 FIELD INVESTIGATION 2

2.1 Soil Borings 2
2.2 Disturbed Sampling (Soil) in boreholes 3
2.3 Undisturbed Sampling (Soil) in boreholes 3
2.4 Groundwater 3

3.0 LABORATORY TESTS 3

4.0 GENERAL SITE CONDITIONS 4

4.1 Site Stratigraphy 4
4.2 Hydrogeology 4

5.0 CONCEPTS FOR FOUNDATION ANALYSIS 5

5.1 Liquefaction Potential 5
5.2 Definition of Gross and Net Bearing Pressure 6

6.0 FOUNDATION ANALYSIS AND RECOMMENDATIONS 7

6.1 General 7
6.2 Recommendations 7
6.3 Variability in Subsurface Conditions 7

7.0 CLOSURE 8
ANNEXURE
o Soil and Rock Profiles & Laboratory test results
o Sample calculation for safe bearing capacity for open foundation

1
INTRODUCTION

1.1 Project Description

M/s. MEGHA Engineering & Infrastructure Ltd has Proposed to taking
up the soil investigation works for Proposed Mono Tower 400kv
Transmission Line For PSP-CPSS 400KV QMDC Line, Pd+09
Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, Andhra Pradesh.

M/s. ANJI GEO SOLUTIONS is carrying out the Geotechnical

Investigations Proposed Mono Tower 400KV Transmission Line for
PSP-CPSS 400KV QMDC Line, PD+09 Tower. Location:AP-2A/0 at
Pinnapuram, Kurnool, Andhra Pradesh.

1.2 Purposes of Study

The overall purposes of this study are to investigate the
stratigraphy at the site and to develop geotechnical recommendations
for foundation design and construction of different structures along the
alignment of the proposed stretch.
To accomplish these purposes, the study was conducted in the
following phases:
(a) drilling One (01) boreholes to required depth in order to
investigate the site stratigraphy and collect disturbed and
undisturbed soil samples for laboratory testing;
(b) testing selected soil samples in the laboratory to determine
pertinent index and engineering properties of the strata; and
(c) analyzing all field and laboratory data in order to develop
engineering recommendations for foundation design and
construction.

2.0 FIELD INVESTIGATION

2.1 Soil Borings
The borings were progressed by Auger to the specified depth or
refusal, whichever is encountered earlier. The work was in general
accordance with IS: 1892-1979.
Standard Penetration Tests (SPT) is conducted by connecting a
split spoon sampler to ‘A’ rods and driving it by 45 cm using a 63.5 kg
hammer falling freely from a height of 75 cm.

2
 The tests were conducted in accordance with IS: 2131-1981.
The number of blows for each 15 cm of penetration of the split spoon
sampler was recorded.
The blows required to penetrate the initial 15 cm of the split
spoon for seating the sampler is ignored due to the possible presence
of loose materials or cuttings from the drilling operation. The
cumulative number of blows required to penetrate the balance 30 cm
of the 45 cm split spoon sampler is termed the SPT value or the ‘N’
value. The ‘N’ values are presented on the soil profile for each
borehole. Refusal to further boring penetration was considered when
the ‘N’ values exceed 100.

2.2 Disturbed Sampling (Soil) in boreholes

Disturbed soil collected in the SPT sampler was preserved in
polythene covers and transported to the laboratory. One more
polythene cover was provided to prevent the loss of moisture during
the transit period.

2.3 Undisturbed Sampling (Soil) in boreholes

Undisturbed samples were collected by attaching 100 mm
diameter thin walled ‘Shelby’ tubes and driving the sampler by light
hammering using a 63.5 kg hammer in accordance with IS: 2132-
1986. The tubes were sealed with wax at both ends. Collection of
undisturbed samples in refusal strata is practically not possible. All
samples were transported to our laboratory at Hyderabad for further
examination and testing.
2.4 Groundwater
Groundwater level was measured in the boreholes 24
hours after drilling and sampling was completed. The measured water
levels are recorded on the individual soil profiles.

3.0 LABORATORY TESTS

Laboratory tests were conducted on selected soil samples,
groundwater samples to determine its index and engineering
properties. The testing procedures were in accordance with current
applicable IS specifications. The following tests were conducted on
selected samples recovered from the boreholes:
On Soil:
Name of Test IS Code No.
Bulk Density IS : 2720 (Part-7)
Grain size analysis IS : 2720 (Part-4)-1985

3
 Name of Test IS Code No.
Specific gravity IS : 2720 (Part-3)-1980
Liquid and plastic limits IS:2720 (Part-5)-1985

Unconfined compression test IS:2720 (Part-10)-1991

Natural moisture content IS:2720(Part-2)-1973

Unconsolidated undrained Direct Shear Test IS : 2720 (Part-13)-1986
On Rock:
Name IS Code No.
of Test
Bulk density IS : 13030-1991
Specific Gravity IS : 1124 - 1974
Water absorption IS : 13030-1991
Crushing strength IS: 9143-1979

All the test results are presented in the Annexure section of this report.

4.0 GENERAL SITE CONDITIONS

4.1 Site Stratigraphy
Based on the boring information, the following subsoil profile
was inferred up to final depth of boreholes:

Depth (m)
Location Strata Description
From To

AP-2A/0 0.00 9.50 Completely Weathered Rock (CWR) or Residual soil

9.50 17.00 Highly Weathered Rock (HWR)

17.00 20.00 Slightly Weathered Rock (SWR)

*All locations of boreholes were given by client

4.2 Hydrogeology:
Based on the measurements in the completed boreholes ground water not
met below existing ground level during the period of our field investigation
(April, 2023).

4
5.0 CONCEPTS FOR FOUNDATION ANALYSIS
5.1 Liquefaction Potential
Liquefaction is defined as the transformation of a granular
material from a solid to a liquefied state as a consequence of increased pore-
water pressure and reduced effective stress (Marcuson, 1978)(1). Increased
pore pressure may be induced by the tendency of granular materials to
compact when subjected to cyclic shear deformation, such as in the event of
an earthquake.
As per IS: 1893-2002, liquefaction is likely to occur in fine sand
(SP) below water tabl e for SPT value less than 15. As per
stratigraphy, Subsurface consists either non-cohesive soil with high
standard penetration resistance, followed by bed rock.
Reviewing all the soil conditions, SPT values and soil gradation,
we are of the opinion that the liquefaction at the site is not likely to
occur during earthquakes.
As per IS: 1893-2002, the project site is in earthquake Zone-II.
The design parameters applicable for Zone-II should be used for the
structural design.
Open Foundations on Soil
Bearing capacity analysis was carried out based on the shear
parameters (c-), as interpreted from field and laboratory tests to
determine the safe net bearing capacity (shear criterion).
The bearing capacity equation used is as follows:
qnet safe = 1 [cNcc dc+ p(Nq -1) q dq+ 0.5 B N d Rw]
F
where :
qnet safe = safe net bearing capacity of soil, based on the
shear failure criterion.
c = cohesion intercept
 = angle of internal friction
 = total unit weight of soil
p = overburden pressure
B = width of foundation
Rw = water table correction factor
F = Factor of safety, taken as equal to 2.5 in accordance with
(1)
Markuson, W.F. (III) (1978), “Definition of terms related to liquefaction”, J. Geotech Engrg.
Div,, ASCE, 104(9), 1197-1200

5
 IS:1904
Nc,Nq,N = Bearing capacity factors which are a function of .
c, q,  = Shape factors.
For Strip footings, c = q =  = 1
For Square footing = c = 1.3, q = 1.2,  = 0.6
dc ,dq, d = Depth factors
For   10, dc = 1 + 0.2 tan (45 + /2) D/B, dq = d = 1
For  > 10, dq = d = 1 + 0.1 tan (45 +  / 2) D/B
Appropriate values have been substituted into the bearing
capacity equation given above to compute the safe net bearing
capacity. The values have been checked to determine the settlement
of the foundation under the safe bearing pressure. The allowable
bearing pressure has been taken as the lower of the two values
computed from the bearing capacity shear failure criterion as well as
that computed from the tolerable settlement criterion.
In predominantly granular soils, settlement analysis has been
performed based on the SPT values in accordance with Clause 9.1.4
of IS 8009 (Part 1) - 1976 Fig.9.
Where applicable (typically where substantial incremental
stresses are anticipated in cohesive strata below groundwater table),
settlement analysis has been performed based on classical theory; as
the sum of elastic settlement and consolidation settlements. The
elastic settlement is calculated in accordance with Clause 9.2.3 of IS
8009 Part 1-1976. The consolidation settlement is computed in
accordance with Clause 9.2.2 of IS 8009 (Part 1)-1976.

5.2 Definition of Gross and Net Bearing Pressure

For the purposes of this report, the net allowable bearing
pressure should be calculated as the difference between total load on
the foundation and the weight of the soil overlying the foundation
divided by the effective area of the foundation. The gross bearing
pressure is the total pressure at the foundation level including
overburden pressure and surcharge load.
The following equations may be used -
qnet = [(Ps + W f +W s) / Af] - Sv
qgross = qnet + Sv = (Ps + W f + W s) / Af

where:
qnet = net allowable bearing pressure

6
 qgross = gross bearing pressure
Ps = superimposed static load on foundation
Wf = weight of foundation
Ws = weight of soil overlying foundation
Af = effective area of foundation
Sv = overburden pressure at foundation level

6.0 FOUNDATION ANALYSIS AND RECOMMENDATIONS

6.1 General
A suitable foundation for any structure should have an
adequate factor of safety against exceeding the bearing capacity of the
supporting soils. Also the vertical movements due to compression of
the soils should be within tolerable limits for the structure. We consider
that foundation designed in accordance with the recommendations
given herein will satisfy these criteria.

6.2 Recommendations
Based on the Geotechnical Investigations and site appraisal, the
following recommendations were given:

 Open(Isolated / Raft) foundation are recommended.

Safe SBP @ SBP @

Bearing 25mm 50mm
Foundation Foundatio *Recommended
Location Capacity Permissible Permissible 2
depth, m n sizes, m SBC, T/m
(shear) Settlement Settlement
t/m2 t/m2 t/m2

AP 2A/0 1.50 201 111 223 70

2.00 215 112 225 80

3.00 14mX14m 224 115 230 85

4.00 274 119 238 95

5.00 304 121 343 100

 Completely Weathered Rock or Residual Soil based on embedment

depth in the computations higher safe bearing capacity is reflected
but it is restricted to not more than 70-100 T/m2.

7
  The actual size and depth of the foundations will be based on the
requirements of the super structure.

 The change in SBC for different foundation sizes is insignificant.

Therefore, the recommended values may be considered applicable
for all sizes of foundations including raft foundation.

6.3 Variability in Subsurface Conditions

Subsurface conditions encountered during construction may
vary somewhat from the conditions encountered during the site
investigation. In case significant variations are encountered during
construction, we request to be notified so that our engineers may
review the recommendations in this report in light of these variations.

7.0 CLOSURE
We appreciate the opportunity to perform this investigation for
you and have pleasure in submitting this report. Please contact us
when we can be of further service to you.

For Anji Geo Solutions

Geotech Consultant

8
 Fig-1: Summary of Soil Profile
G.L:338.100
R.L,m BH No:AP 2A/0
Location:AP 2A/0
00.0m-
N Values
55 Blows @ 2cm >100
55 Blows @ 2cm >100
5.00m-
LEGEND :
Soft Disintegrated Rock
Fractured Rock
Hard Rock
9.50m- CR/RQD
10.00m-
50/12
36/0
49/0
50/10
48/25
15.00m- 47/0
45/0
17.00m- 50/13
42/33
55/53
20.00m- 20.00m- 58/53
 Location TERMINATION G.L
Proposed Mono Tower 400kv Transmission Line For PSP-CPSS 400KV QMDC Line, AP-2a//0 DEPTH,M 338.1
Pd+09 Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, Andhra Pradesh.
WATER TABLE,M : Start Date: 17/4/2023
20.00
Co-Ordinates E:204697.425,N:1728404.104 Not met End Date: 19/4/2023
SPT - Details Grain Size Analysis Atterberg Limits Direct Shear Test

Moisture Content %
Free swell Index

Angle of Internal
Specific Gravity
Plasticity Index

Bulk density
15-30 cm

30-45 cm

Sample No.

Dry Density
SOIL DESCRIPTION
0-15 cm

Depth (m)
N-Value

Confining

Cohesion
Plastic %
Gravel %

Pressure
3

Intercept
Liquid %

gms/cm
Sand %

Friction
2

2
m %

Kg/cm

Kg/cm
Silt %

Clay

%
0.00
55 Blows 0cm >100 1.50 SPT/DS Completely Weathered Rock (CWR) or Residual soil 5 91 4 0 NP NP NP 2.65 1.92 1.77 8.7 0 33

1.50
55 Blows 0cm >100 3.00 SPT/DS Completely Weathered Rock (CWR) or Residual soil

3.00
4.50 DS Completely Weathered Rock (CWR) or Residual soil 8 86 6 0 NP NP NP 2.64 2.11 1.95 8.1 0 35

4.50
6.00 DS Completely Weathered Rock (CWR) or Residual soil

6.00
7.50 DS Completely Weathered Rock (CWR) or Residual soil 3 95 2 0 NP NP NP 2.64 2.19 2.03 7.9 0 34

7.50
9.00 DS Completely Weathered Rock (CWR) or Residual soil

9.00
9.50 DS Completely Weathered Rock (CWR) or Residual soil

in Residual Soil, The grain size analysis was done on wash bore samples (SPT/DS) and
classifying it as pure sand would be erroneous considering the fact that fine grained fraction (clay
or silt) is washed away. Having well graded or poorly graded sand is unlikely considering SPT
refusal, Using this density, direct shear tests were carried out on remoulded samples
 Location CH No
Proposed Mono Tower 400kv Transmission Line For PSP-CPSS 400KV
AP-2a/0 Date
BORE HOLE LOG QMDC Line, Pd+09 Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, TERMINATION DEPTH, M
Andhra Pradesh.
Water Level,m 17./4/2023
20.00
Not met 19./4/2023
Location : See Fig No. 1 Type of Boring: . Rig:

Point Load Index

Specific Gravity

UCC Strength,
Absorption(%)
Drill Run (m)

Density g/cc
Penetration

Sample No
Depth (m)

RQD (%)

Bits Used

Remarks
N Value

kg/cm2

kg/cm2

Water Loss
CR(%)

Water
Rock Description

9.50

10.50 1.00 Core Samples 50% 12% Highly Weathered Rock (HWR) 2.79 0.25 48 2.72

11.00 0.50 Core Samples 36% 0% -do-

12.00 1.00 Core Samples 49% 0% -do-

13.00 1.00 Core Samples 50% 10% -do- 2.77 0.29 42 2.75

14.00 1.00 Core Samples 48% 25% -do-

15.00 1.00 Core Samples 47% 0% -do-

16.00 1.00 Core Samples 45% 0% -do- 2.75 0.32 53 2.79

17.00 1.00 Core Samples 50% 13% -do-

18.00 1.00 Core Samples 42% 33% Slightly Weathered Rock (SWR) 2.8 0.26 590 2.81

19.00 1.00 Core Samples 55% 53% -do-

20.00 1.00 Core Samples 58% 53% -do- 2.82 0.24 612 2.84
 Sheet No.3

BEARING CAPACITY ANALYSIS FOR

SHALLOW FOUNDATIONS
Analysis as per IS 6403-1981

Project : Proposed Mono Tower 400kv Transmission Line For PSP-CPSS 400KV QMDC
Line, Pd+09 Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, Andhra Pradesh.

The bearing capacity equation is as follows :

qnet safe = (1/FS){cNcz cdc+q(Nq-1)z qdq+0.5BgNgz gdgRw}
where:
qnet safe = safe net bearing capacity c = cohesion intercept
q = overburden pressure B = Foundation width
g = Bulk density of soil below founding level
Rw = Water table correction factor FS = Factor of safety
Nc, Nq, Ng = bearing capacity factors, which are a function of f
dc, dq, dg = Depth factors
zc, zq, zg = Shape factors
Soil parameters : Bulk Density
c= 0.00 T/m2 f = 33.0 degrees GENERAL SHEAR FAILURE Profile
c' = 0.00 T/m2 f'= 23.4 degrees LOCAL SHEAR FAILURE Depth, m g
General Shear Failure : Nc = 38.64 Nq = 26.09 Ng = 35.19 From To T/m3
'
Local Shear Failure : Nc' = 18.56 Nq' = 9.03 Ng = 8.69 0.0 9.5 1.90
9.5 20.0 2.30
Factor of safety = 2.5 as per IS 1904-1986

Design Water Table depth = not met

Rw factor: Constant value(V) for worst condition or
calculate(C) based on WT Depth ? : C
Depth factor to be considered ? Y
For computation of Depth Factor, depth below GL to be ignored to account for loose
soils,poorly compacted backfill above foundation, scour etc. = 0.0 m
FAILURE CRITERIA : General SHEAR FAILURE

qnet safe ,Safe Net

Depth,m

Foundation Depth factors Depth factors

FOUN- Shape Factors Bearing
Dimensions DATION Rw (GSF) (LSF) T/m2
Capacity
B, m L, m SHAPE zc zq zg dc dq dg dc ' dq' dg ' GSF LSF
T/m2
14.0 14.0 square 1.5 1.00 1.30 1.20 0.80 1.04 1.02 1.02 201.5 201.5
14.0 14.0 square 2.0 1.00 1.30 1.20 0.80 1.05 1.03 1.03 215.6 215.6
14.0 14.0 square 3.0 1.00 1.30 1.20 0.80 1.08 1.04 1.04 244.5 244.5
14.0 14.0 square 4.0 1.00 1.30 1.20 0.80 1.11 1.05 1.05 274.2 274.2
14.0 14.0 square 5.0 1.00 1.30 1.20 0.80 1.13 1.07 1.07 304.4 304.4
 Sheet No.4

SETTLEMENT ANALYSIS FOR

SHALLOW FOUNDATIONS BASED ON N - VALUES
Analysis as per IS:8009(Part 1)-1976 , Clause 9.1.4

Project : Proposed Mono Tower 400kv Transmission Line For PSP-CPSS 400KV QMDC Line,
Pd+09 Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, Andhra Pradesh.

Design Water Table Depth : not met

R w factor : Calculate (C) based on water table
depth or Fixed Value(V) for worst condition : C
Fox's Depth Factor to be considered ? Y
Depth to be ignored in Depth Factor Computation
for loose soils, poorly compacted backfill, scour, etc. 0.0 m
Tolerable Total Settlement 25.0 mm
Settlement
Rigidity Factor,

2
Net Allowable

Pressure, T/m
Fox's Depth
Foundation
Foundation

Foundation

@ 1kg/cm2
Length,m

Factor, df
N-value
Depth,m
Width,m

Design

Bearing

(as read off

Shape Rw
dr

from graph),
mm

14.0 14.0 1.5 square 100.0 2.9 1.00 0.98 0.8 111.7
14.0 14.0 2.0 square 100.0 2.9 1.00 0.97 0.8 112.9
14.0 14.0 3.0 square 100.0 2.9 1.00 0.95 0.8 115.3
14.0 14.0 4.0 square 100.0 2.9 1.00 0.92 0.8 119.0
14.0 14.0 5.0 square 100.0 2.9 1.00 0.90 0.8 121.7
 Sheet No.4

SETTLEMENT ANALYSIS FOR

SHALLOW FOUNDATIONS BASED ON N - VALUES
Analysis as per IS:8009(Part 1)-1976 , Clause 9.1.4

Project : Proposed Mono Tower 400kv Transmission Line For PSP-CPSS 400KV QMDC Line,
Pd+09 Tower. Location:AP-2A/0 At Pinnapuram, Kurnool, Andhra Pradesh.

Design Water Table Depth : not met

R w factor : Calculate (C) based on water table
depth or Fixed Value(V) for worst condition : C
Fox's Depth Factor to be considered ? Y
Depth to be ignored in Depth Factor Computation
for loose soils, poorly compacted backfill, scour, etc. 0.0 m
Tolerable Total Settlement 50.0 mm
Settlement
Rigidity Factor,

2
Net Allowable

Pressure, T/m
Fox's Depth
Foundation
Foundation

Foundation

@ 1kg/cm2
Length,m

Factor, df
N-value
Depth,m
Width,m

Design

Bearing

(as read off

Shape Rw
dr

from graph),
mm

14.0 14.0 1.5 square 100.0 2.9 1.00 0.98 0.8 223.5
14.0 14.0 2.0 square 100.0 2.9 1.00 0.97 0.8 225.8
14.0 14.0 3.0 square 100.0 2.9 1.00 0.95 0.8 230.5
14.0 14.0 4.0 square 100.0 2.9 1.00 0.92 0.8 238.1
14.0 14.0 5.0 square 100.0 2.9 1.00 0.90 0.8 243.3
Annexure – 1

SITE PHOTOS