Soil Investigation Report For Planning Solution,

G+3 Residential Housing Scheme, T.P. Scheme No.19,

Survey No. 368, Ahmedabad.

Month : March 2011

INTRODUCTION:

Soil investigation work for Planning Solution, G+3 Residential Housing Scheme, T.P.
Scheme No.19, Survey No. 368, Ahmedabad was carried out by the Unique Engineering
Testing and Advisory Services laboratory.

FIELD TESTS:

1) Drilling 1 no of 150 mm φ bore hole with casing whenever required up to maximum

depth of 8.0 m from ground level.
2) Carry out Standard Penetration Test (SPT) at every 1.0 M interval alternate to
undisturbed sampling or continuous SPT at 1.0 M depending on cohesive & non-
cohesive formation.
3) Collecting disturbed soil sample at every meter interval or as per the stratification
of soil, recording depth at which soil Changes.
4) Collecting undisturbed samples (UDS) at 1.0 M interval alternate to S P Test or
continuous UD Sample at 1.0 M interval if subsoil is cohesive.

LABORATORY TEST:

1) Water content & unconfined compression test on selected samples of standard

penetration test.
2) Field Density, Moisture content and Dry Density of undisturbed samples.
3) Grain size Analysis of SPT samples, UD samples and disturbed samples covering
each soil strata.
4) Atterburg’s Limit for samples as per above.
5) Specific gravity Test for samples as per 3.
6) Shrinkage Limit / Free Swell Test / Differential Swell test for selected samples
judged to be expansive soil.
7) Test for shear properties of selected samples.
 a) Unconfined compressive Strength on saturated cohesive soils.
b) Triaxial Shear Test under UU / CU condition with or without pore pressure
measurement as per in situ conditions. Normally soft cohesive saturated
samples will be consolidated at average Overburden pressure.
The common practice adopted in the field and laboratory testing by & large are as
per I S code as indicated below: unless otherwise stated in report.

DRILLING:
Drilling of 150 mm φ borehole is carried out by shell and Auger method above
water table. Water is added while drilling but stopped at enough height above the U D
sampling or S P Test levels to avoid disturbance.
Drilling below water table is made by percussion method. Casing is required to be
lowered if the boreholes do not retain its shape. Care is taken that ground water level is
maintained during the drilling and particularly before testing or sampling levels. In no case
casing is allowed to advance below the bottom of borehole. Chiseling is carried out if
required while drilling.

STANDARD PENETRATION TEST:

The Standard Penetration Tests are carried out as per I. S. 2131: 1981. In general
the tests are conducted at 1.0 M interval alternate to the undisturbed sampling or as
dictated by soil strata existing.
Before testing, the borehole is cleaned properly and Split Spoon Sampler is
centrally seated in borehole. In case of SPT to be conducted below water table care is
taken that casing position is above the borehole depth. The water level in borehole is
maintained above or at least at the water table.
A standard hammer of 63.5 Kg. is dropped from a height of 75 cms. and the no. of
blows for penetration of Split Spoon Sampler for 0-15, 15-30 and 30-45 cms. are noted
in Table – 3. Standard Penetration Test value Ns is considered for 15-45 cms. penetration
values. Sample for moisture content is collected in moisture cans. For non-plastic silts and
fine Sands Ns value is corrected for effective overburden pressure and dilatancy Correction
is added for tests conducted below water table Results are shown in Table – 3.

DISTURBED AND UNDISTURBED SAMPLES:

Disturbed samples from shell or from Split Spoon Sampler is collected in polythene
bags with proper levels such that we shall get the data of 0.5 Mt. interval or change in
strata.
Undisturbed samples in 38 mm φ Shelby tubes are Collected alternate to Standard
Penetration Test at 3.0 Mt. interval. The sampling tube is connected to the rod by jarring
link in case of 38 mm φ Shelby tube or otherwise in case of 75 or 100 mm φ tube, ‘A’ drill
rods are connected by suitable adopter with ball check value. Two or three undisturbed
Samples are collected at same depth in case of 38 mm φ tube to get sufficient sample for
physical property tests. Before lowering the sampler, the bore is cleaned properly and
sampling tube is lightly oiled from inner and outer side.
Sampling tube is pushed into the borehole by pressure hammering as per the soil
stiffness. The sampling tube is immediately waxed after covering with aluminum foil.
In case of medium to coarse, non-cohesive, sand samples, where sampling is
unsuccessful, Standard Penetration Test is carried out on cleaning the borehole.

PHYSICAL PROPERTIES:

The moisture cans collected from S P T samples from the field are weighed and
placed in oven for drying to determine natural moisture content (NMC). Results are
tabulated in Table – 3.
U D samples are extracted using screw type extractor and samples are prepared as
per the required sizes of the test to be performed. Before extracting from tube, weight and
volume of sample are noted. Average bulk density is calculated in laboratory and samples
are placed in oven to get the field moisture content for computing the dry density. Results
are tabulated in Table – 4.
Specific gravity with specific gravity bottle / pycknometer is calculated as per I. S.
2720 (part – 3, section 1&2): 1980. Results are tabulated in Table –4. From the results of
dry density and specific gravity the saturation of sample in % is calculated which is a useful
data for deciding the condition of triaxial shear test
Grain size analysis is made by I. S. sieves and sieving is done on timer switch
electrically operated sieve shaker I.S sieves commonly used are 4.75 mm, 2.00 mm, 1.00
mm 425 microns, 250 microns and 75 microns. For the coarse grain soil a graph of partial
size v/s cumulative % finer is plotted. For fine grain soil wet analysis is made on plummet
balance, modern version of hydrometer. Mechanical digital single pan balance of 1 kg
capacity with 0.1 gram least count is used. Results are tabulated in Table – 5.
Liquid limits and Plastic limits tests are carried out with distilled water as per I. S.
2720 (part – 5): 1985. The samples are tested at a minimum of 24 hours after the addition
of water. For liquid limit test cone penetration method is adopted but occasionally value is
checked on Casagrande standard.
For the foundation soil sample shows sample shows high plasticity are checked for
swelling and shrinkage. Firstly for rough estimate, free test as per I. S. 2720 (part – 40):
1977 is being carried out and getting positive indication of swelling. Shrinkage limit test is
carried out as per I. S. 2720 (part – 6): 1972.

SHEAR PROPERITIES:

Shear tests are carried out by three methods.

1) Unconfined compressive strength as per I. S. 2720 (part – 10): 1973 for the
saturated plastic soil undisturbed samples and cores of SPT samples.
2) Triaxial shear test is carried out on sample size of 38 mm φ and 76 mm in height on
motorized 30-speed load frame with digital display arrangements for load and
 pore-pressure. The confining pressure 3 is applied to the cell by oil-water constant
pressure system. The tests are carried out for the condition.
a) Unconsolidated undrained (UU) test without pore-pressure measurement
as per I.S. 2720 (part – 11): 1971.
b) Consolidated undrained (CU) test with or without pore-pressure
measurement as per I.S. 2720 (part – 11): 1981.
The condition decided on type of sample and water table condition or
designers specifications.
3) Direct box shear test is carried out on non-plastic medium to coarse sand soil as per
I.S. 2720 (part – 13): 1986.
The graph for triaxial shear test is plotted by modified method where X-axis
represents ½(σ1+σ3) and Y-axis represents ½½(σ1- σ3)
 I.S. CLASSIFICATION
GW: Well graded gravels, gravel-sand mixture or no fines.
GP: Poorly graded gravels or gravel sand mixture, little or no fines.
GM: Silty gravels, poorly graded gravel-sand-silt mixtures.
GC: Clayey gravels, poorly graded gravel-sand-clay mixtures.
SW: Well-graded sands, gravely sands; little or no fines.
SP: Poorly graded sands or gravely sands, little or no fines.
SC: Silty sands, poorly graded sand-silt mixtures.
SC: Clayey sands, poorly graded sand-clay mixtures.
ML: Inorganic silt and very fine sands rock flour; silty or clayey fine sands or clayey silts
with non-to low plasticity.
CL: Inorganic clays, gravely clays, sandy clays, silty clays, lean clays of low plasticity.
OL: organic silts and organic silty clay of low plasticity.
MI: Inorganic silts, silty or clayey fine sands or clayey silts of medium plasticity.
CI: Inorganic clays, gravely clays, sandy clays, silty clays, lean clays of medium plasticity.
OI: Organic silts and organic silty clays of medium plasticity.
MH: Inorganic silt of highly compressibility, micaceous or diatomaceous fine sandy or silty
soils, elastic silts.
CH: Inorganic clays of high plasticity, fat clays.
OH: Organic Clays of medium to high plasticity.
Pt: Peat and other highly organic soil with very high compressibility.
Project No: 10110337: Planning Solution, G+3 Residential Housing Scheme, T.P. Scheme
No.19, Survey No. 368, Ahmedabad.

Calculation for Allowable Bearing Capacity

= c Nc sc dc ic + q (Nq - 1) sq dq iq + ½ B γ Nγ sγ dγ iγ W
= 0 × 24.488 × 1.3 × 1.326 × 1 + 0.34 × (13.756 - 1) × 1.2 × 1.163 × 1 + 0.5 × 200 × 0.0017 × 15.488 × 0.8 ×
1.163 × 1 × 0.5
= 0 + 6.053 + 1.225
= 7.278 Kg/cm²
= 72.78 T/m²
Where
c = Cohesion = 0 kgf/cm²
q = Effective surcharge at base of fdn = 0.34 kgf/cm²
B = Width of footing = 200 cm
 = Bulk unit weight of foundation soil = 0.0017 Kgf/cm³
W' = Correction factor for location of water table = 0.5
Ø = Angle of shearing resistance of soil in degrees = 27
Nc = Bearing Capacity Factor = 24.49
Nq = Bearing Capacity Factor = 13.76
N = Bearing Capacity Factor = 15.49
sc = Shape factor = 1.3
sq = Shape factor = 1.2
s = Shape factor = 0.8
dc = Depth Factor = 1.326
dq = Depth Factor = 1.163
d = Depth Factor = 1.163
ic = Inclination Factor = 1
iq = Inclination Factor = 1
i = Inclination Factor = 1

Safe Bearing Capacity

= 24.26 T/m² [Considering a Safety Factor of 3]
Settlement Calculation

Settlement in Non-Cohesive Layer from 0 to 6 m (S1)

[from graph - Fig 9 (IS 8009 Part 1 - 1976)], for Width 'B' = 2 m and N = 30, Settlement
= 8.1 mm (per Kg/cm² of Pressure) x 2.43 Kg/cm² (Foundation Pressure) / 0.5 (Correction for Water
Table at Foundation Level)
= 39.37 mm

Total Settlement
Sf = S1
= 39.37
= 39.37 mm

Applying Correction for Effect of Depth of Foundation

Sfd = Sf × Depth Factor
= 39.37 × 0.72
= 28.52 mm
Where
Depth Factor = 0.72 [from Fox's Correction Curves (Fig 12, IS 8009) for (L B) / D = 1 and L
/B = 1]

Allowable Bearing Capacity

= 24.3 T/m² for width of foundation 2.0 mts and Settlement of 28.5 mm

For UET&AS

Authorized Signatory
DISCUSSION & CONCLUSIONS:

Geotechnical exploration for low-rise structure was explored with single borehole 7.0
m depth the geotechnical exploration shows:

1. The water table is below termination level.

2. The strata 0.0 to 7.0 m depth is SM type silty sand having moisture content
between 3 to 6 %, Ns = 10 at 1.0 m depth, dry density γdavg = 1.50 g/cc at 2.0m
depth and shear parameters C=0.0 & φ=30.25° at 2.0 m depth.
3. The foundation depth recommended for low-rise building is 2.0 m below ground
level on SM type silty sand.
4. As water table is below pressure Zone, considering worst condition of temporary
flooding, considering general shear failure, design gross bearing capacity
recommended for isolated footing will be 24 t/m2.
5. Foundation soil shall be properly compacted before PCC is laid to avoid
differential settlement.
For UET&AS

Authorized Signatory
 TABLE - 1
FIELD PROGRAMME OF TESTS

Project No. : Bore Hole No. : 1

10110337
Location of Bore Hole : RL of Ground Level (mt):

Depth in mts. Visual Soil Description Field Tests Remarks

00.00 Brownish yellow colored slty sand DS

01.00 SPT N=10

02.00 UDS

03.00 SPT N=25

04.00 UDS

05.00 SPT N=36

06.00 SPT N=39

07.00 SPT N=42

 TABLE - 2
LABORATORY PROGRAMME

Project No. : Bore Hole No. : 1

10110337
Depth Particle Shrinkage Shear Test
Type of N. M. C. Density Specific Size Atterberg Limit / (UCC/Trx/ Other
Sample Gravity Analysis Limits Free Swell Box/Vane) Tests
0.00/D Yes Part Yes

1.00/S Yes Part Yes

2.00/U Yes Yes Yes Part Yes FRS BOX

3.00/S Yes Part Yes

4.00/U Yes Yes Yes Part Yes FRS BOX

5.00/S Yes Part Yes

6.00/S Yes Part Yes

7.00/S Yes Part Yes FRS

 TABLE - 3
RESULTS OF STANDARD PENETRATION TEST

Project No. : Bore Hole No. : 1

10110337
Depth No. of Blows for Penetration Ns (Blows Nc(Corrected N. M. C.
in mts. 0 - 150 mm 150 - 300 mm 300 - 450 mm /300 mm) value of Ns) (in %)

1.00 03 04 06 10 15 4.28

3.00 06 11 14 25 29 3.72

5.00 07 16 20 36 36 4.53

6.00 10 17 22 39 37 3.99

7.00 09 18 24 42 37 6.52
 TABLE - 4
INSITU DENSITY, MOISTURE CONTENT, DRY DENSITY & SPECIFIC GRAVITY

Project No. : Bore Hole No. : 1

10110337
Depth Bulk Density Natural Moisture Dry Density Specific
Saturation
Sample (mts.) in gms/cc Content (%) in gms/cc Gravity

2.00 1.61 6.50 1.51 2.70 0.22

4.00 1.78 4.31 1.71 2.69 0.20

 TABLE - 5
PARTICLE SIZE ANALYSIS

Project No. : Bore Hole No. : 1

10110337
Depth Gravel in % Sand in % Silt in %
Soil Strata +
Sample Type (>4.75 mm) (4.75 - 2 mm) (2mm - 425µ) (425 - 75 µ) Clay in %
0.00 to 7.00 0.00 /D 0 0 2 50 48

0.00 to 7.00 1.00 /S 0 0 8 44 48

0.00 to 7.00 2.00 /U 0 0 8 58 34

0.00 to 7.00 3.00 /S 0 0 8 53 39

0.00 to 7.00 4.00 /U 0 1 6 53 40

0.00 to 7.00 5.00 /S 0 0 16 46 38

0.00 to 7.00 6.00 /S 0 0 10 56 34

0.00 to 7.00 7.00 /S 0 1 15 44 40

 TABLE - 5A
PARTICLE SIZE DISTRIBUTION

Project No. Bore 1

: 10110337 Hole No.
Depth Gravel Sand in %
Soil Strata
: Silt in %
Type of in % Coarse Medium Fine +
Sample (>4.75 mm) (4.75 - 2 mm) (2mm - 425µ) (425 - 75 µ) Clay in %

0.00/D 0.00 to 7.00 0 0 2 50 48

1.00/S 0.00 to 7.00 0 0 8 44 48

2.00/U 0.00 to 7.00 0 0 8 58 34

3.00/S 0.00 to 7.00 0 0 8 53 39

4.00/U 0.00 to 7.00 0 1 6 53 40

5.00/S 0.00 to 7.00 0 0 16 46 38

6.00/S 0.00 to 7.00 0 0 10 56 34

Clay Silt Sand Gravel

100 Fine Medium Coarse

90

80

70

60

50

40

30

20

10

0
0.001 0.01 0.1 1 10
PARTICLE SIZE (mm)
 TABLE - 5A
PARTICLE SIZE DISTRIBUTION

Project No. Bore 1

: 10110337 Hole No.
Depth Gravel Sand in %
Soil Strata
: Silt in %
Type of in % Coarse Medium Fine +
Sample (>4.75 mm) (4.75 - 2 mm) (2mm - 425µ) (425 - 75 µ) Clay in %

7.00/S 0.00 to 7.00 0 1 15 44 40

Clay Silt Sand Gravel

100 Fine Medium Coarse

90

80

70

60

50

40

30

20

10

0
0.001 0.01 0.1 1 10
PARTICLE SIZE (mm)
 TABLE - 6
ATTERBERG LIMITS

Project No. Bore Hole No. 1

: 10110337 :
Depth Liquid Plastic Plasticity Shrinkage Freeswell I.S. Classi-
Soil Strata
Sample Type Limit Limit Index Limit Index fication
0.00 to 7.00 0.00 /D 25 - - SM

0.00 to 7.00 1.00 /S 28 - - SM

0.00 to 7.00 2.00 /U 24 - - 06 SM

0.00 to 7.00 3.00 /S 24 - - SM

0.00 to 7.00 4.00 /U 26 - - 06 SM

0.00 to 7.00 5.00 /S 22 - - SM

0.00 to 7.00 6.00 /S 24 - - SM

0.00 to 7.00 7.00 /S 21 - - 06 SM

 TABLE - 7C
BOX SHEAR TEST

Project No. : 10110337 9 Bore Hole No. : 1

Depth Sample Type Normal Stress Shearing Stress Shear Values from Graph
Sample (UD/Rm) σin Kg/cm² τin Kg/cm² Cuu (Kg/cm²) Øuu (Kg/cm²)

2.00 Undisturbed 0.70 0.41 0.00 30.24

Undisturbed 1.20 0.70

Undisturbed 1.70 0.99

BOX SHEAR GRAPH

0
0
σn (in 1Kg/cm²) 2
 TABLE - 7C
BOX SHEAR TEST

Project No. : 10110337- 9 Bore Hole No. : 1

Depth Sample Type Normal Stress Shearing Stress Shear Values from Graph
Sample (UD/Rm) σin Kg/cm² τin Kg/cm² Cuu (Kg/cm²) Øuu (Kg/cm²)

4.00 Undisturbed 0.70 0.46 0.00 33.45

Undisturbed 1.20 0.79

Undisturbed 1.70 1.12

BOX SHEAR GRAPH

0
0
σn (in 1Kg/cm²) 2
 SUMMARY OF GEOTECHNICAL EXPLORATIONS
Project No. : 10110337 Bore Hole Started on : 10-03-11 Depth of Water Table : Below Termination Level
Bore Hole No. :1 Bore Hole Completed on : 10-03-11 R. L. of Ground Level :
Method of Drilling : SHELL & AUGER Diameter of Bore Hole : 150 mm Location of Bore Hole :

I. S. Field Test Ns Rock Natural Density Spe- Particle Size Atterberg Shri- Free Shear Properties
Depth /Samples No. of Properties Moist. (in gms/cc) Analysis Limits Additional
in Classi- Visual Soil Description Gra- nkge swell Test C Ø Tests or
SPT UDS Blows per C.R. RQD Content Gr. Sn Silt+ LL PL PI Lim. Indx Type (Kg/ in
metres fication VST DS 300 mm % % % Bulk Dry vity % % Clay % % % % % cm²) Deg. Remarks
00.00 Brownish yellow colored slty sand DS 3.47 0 52 48 25 - -

01.00 SPT 10 4.28 0 52 48 28 - -

02.00 UDS 6.50 1.61 1.51 2.70 0 66 34 24 - - 6 Buu 0.00 30.2°

03.00 SPT 25 3.72 0 61 39 24 - -

SM

04.00 UDS 4.31 1.78 1.71 2.69 0 60 40 26 - - 6 Buu 0.00 33.5°

05.00 SPT 36 4.53 0 62 38 22 - -

06.00 SPT 39 3.99 0 66 34 24 - -

07.00 SPT 42 6.52 0 60 40 21 - - 6

SPT - Standard Penetration Test DS - Disturbed Sample Gr - Gravel LL - Liquid Limit PI - Plasticity Index Cv - Coeff. of Consolidation C.R. - Core Recovery
UDS - Undisturbed Sample VST - Vane Shear Test Sn - Sand PL - Plastic Limit C, Ø - Shear Parameters Mv - Coeff. of Volume Change RQD - Rock Quality Designation

UNIQUE ENGINEERING TESTING AND ADVISORY SERVICES

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