Ssir Rggvy Odiga Final

SUB-SURFACE

INVESTIGATION

REPORT

PROPOSED

33/11kV SUB-STATION ODGI

(RGGVY PACKAGE: SAR-A)

Sun- Tech N A B L A C C R E D I T E D T E S T H O U S E

I S O 1 7 0 2 5 : 2 0 0 5 & I S O 9 0 0 1 : 2 0 0 8

T-1523

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Sun-Tech

2

SUB-SURFACE INVESTIGATION REPORT

PROPOSED 33/11KV SUB-STATION LOCATION:

ODGI/ SARGUJA/ CHHATISGARH

Job Code: S530910

SUBMITTED TO:

OWNER: CHHATISGARH STATE POWER DISTRIBUTION COMPANY LTD.

CONSULTANT: POWER GRID CORPOARTION OF INDIA LTD.

CONTRACTOR: JYOTI STRUCTURES LTD.

INVESTIGATIONS DONE BY:

Sun-Tech HI-230, HARMU HOUSING COLONY, RANCHI-12, JHARKHAND

TEL: 0651-2242954, 6003411,FAX: 0651-2243889

E-MAIL: [email protected]. VISIT US AT: www.suntech.co.in

This document is the property of Sun-Tech, Hi-230, Harmu Housing Colony, Ranchi-12 .

Any unauthorised employment or reproduction, in full or part is forbidden.

Sun-Tech, Hi-230, Harmu Housing Colony, Ranchi-12, Jharkhand, India , 2010

THE LABORATORY TESTS WERE CONDUCTED AT OUR LABORATORY NABL ACCREDITED (ISO 17025:2005) AND ISO

9001:2008 CERTIFIED AT HI-230, HARMU HOUSING COLONY, RANCHI-12, JHARKHAND.

Sun-Tech

Sub-Surface Investigation Report CODE:S530910

33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A ii

Table Of Contents__________________

1.0 INTRODUCTION 1.1 Project Description 1.2 Purposes of Study 2.0 FIELD INVESTIGATIONS

2.1 Soil Borings 2.2 Rock Drilling 2.3 Groundwater

3.0 LABORATORY TESTS 4.0 GENERAL SITE CONDITIONS

4.1 Site Stratigraphy 4.2 Lithology 4.3 Underground water 4.4 Seismicity

5.0 FOUNDATION ANALYSIS AND RECOMMENDATIONS 5.1 General 5.2 Foundation Type and Depth 5.3 Shallow Foundations 6.0 GENERAL COMMENTS 7.0 REFERENCES

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A iii

1. INTRODUCTION 1.1. Project Description

M/s. Jyoti Structures Ltd. Valecha Chamber’s, 5-6th Floor, New Link Road,

Oshiwara, Andheri (W) has undertaken construction of a new Sub-Station of

33/11 kV at Odgi, Sarguja in Chhatisgarh State under Rural Electrification works

in Sarguja District under RGGVY package# SAR-A for the Chhatisgarh State

Power Distribution Company Limited. M/s. Power Grid Corporation of India Ltd.

are the Consultants of the Project.

The proposed Sub-Station will have Office buildings and foundations for various

electric equipments.

The current study is a detailed investigation for comprehensive assessment of

the site conditions, and inputs for foundation design of the various structures of

Sub-Station.

A layout plan showing the location of various boreholes is illustrated in the

annexure. This report presents the results of the investigation and our

recommendations based on the available geotechnical data.

1.2. Purposes of Study

The overall purpose of these investigations is to investigate the transmission

route and to develop geotechnical recommendation for foundation design and

construction. To accomplish these purposes, the study was conducted in the

following phases:

(a) Drilling Three nos. boreholes through soil and up to refusal to determine site

Stratigraphy and to collect disturbed and undisturbed soil samples for laboratory

testing;

(b) Conducting Dynamic Cone Penetration test at three locations.

(c) Testing selected soil samples in the laboratory to determine pertinent index and

engineering properties; and

(d) Analyzing all field and laboratory data to develop foundation design and

construction recommendations.

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A iv

2. FILED INVESTIGATION

2.1. Soil Borings

The boreholes were progressed using a hand operated auger to the Specified depth or

refusal, whichever is encountered earlier. The diameter of the borehole was 150 mm. Where

caving of the borehole occurred, casing was used to keep the borehole stable. The work was in

general accordance IS: 1892-1979.

Standard Penetration Test (SPT) was conducted in the borehole at 1.5 m interval by

connecting a split spoon sampler to ‘A’ rods and driving it by 45 cm. The tests were conducted

in accordance with IS: 2131-1981.

The numbers of blows for each 15 cm of penetration were 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 sampling interval is

termed the SPT value of the ‘N’ value.

The ‘N’ values are presented on the profiles for each borehole. Refusal to further boring

penetration was considered when the ‘N’ values exceed 50 or when practical refusal to further

penetration by shell and auger was encountered.

Where the ‘N’ value exceeds 50, the penetration of split spoon sampler (after initial

seating) is recorded together with the number of blows given of the sampler. Where the seating

blow count exceeds 50, the ‘N’ value is recorded as “Ref” on the soil profile.

SPT ‘N’ values are correlated with relative density of non-cohesive stratum and with consistency of cohesive stratum:

CORRELATION FOR

CLAY/PLASTIC SILT

CORRELATION FOR SAND/NON-PLASTIC

SILT Consistency Penetration Value

(blows) Relative Density Penetration

Value (blows) Very Soft 0-2 Very Loose 0-4

Soft 3-4 Loose 5-10

Medium Stiff 5-8 Medium 11-30 Stiff 9-16 Dense 31-50

Very stiff 17-32 Very Dense >50 Hard >32

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A v

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.

Undisturbed Sampling (Soil) in Boreholes

Undisturbed samples are collected using 100mm diameter and 450mm long MS tubes

provided with sampler head with ball check arrangement. Undisturbed soil samples

are usually collected in soft to stiff clayey soil strata. Collection of undisturbed samples

in refusal strata is practically not possible. All samples were transported to our laboratory

at Ranchi for examination and testing.

2.2. Groundwater

Groundwater level was measured in the boreholes 24 hours after drilling and

sampling was completed. No water table was found in the bore holes.

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A vi

3. LABORATORY TESTS

The laboratory testing has been carried out in our laboratory at Ranchi. The

quality procedures in our laboratory conform to ISO/IEC-17025-2005 and ISO

9001:2008.

The laboratory testing programme was aimed at verifying the field classifications

and developing parameters for engineering analysis. All testing was performed in

accordance with the current applicable IS specifications. The following tests were

conducted on selected soil and water samples recovered from the borehole:

On Soil :

Laboratory Test IS : Code Referred

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

Grain size analysis IS : 2720 (Part-4)-1985

Liquid & Plastic limit IS : 2720 (Part-5)-1985

Specify Gravity IS : 2720 (Part-3)-1980

Unconsolidated Undrained Triaxial shear test IS : 2720 (Part-11)-1983

Consolidated Drained Direct Shear Test IS : 2720 (Part-13)-1986

Unconfined Compression Test IS : 2720 (Part-10)-1991

Determination of pH value IS : 2720 (Part-26)-1987

Determination of Sulphate content IS : 2720 (Part-27)-1977

Chemical

Analysis of

soil* Determination Chloride content IS : 3025 (Part-32)-1988

Determination of pH value IS : 3025 (Part-11)-1996

Determination of total soluble

sulphate

IS : 3025 (Part-24)-1998 Chemical

Analysis of

water* Determination of Chloride content IS : 3025 (Part-32)-1993

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

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A vii

4.0 GENERAL SITE CONDITIONS

4.1 Site Stratigraphy

The boreholes are evenly spaced. The plot is about 1.50m above the

existing road level. The soil strata in the plot are uniform. In general, an

overburden of stiff to very stiff high to medium plastic silty sandy gravelly clay

is found up to 3.00-5.00m depth over dense completely weathered rocks.

The Bore logs in the annexure present the detailed Stratigraphy, cross sections and nature of soil at the borehole locations

4.2 SEISMICITY:

The area falls under Zone-III as classified by Bureau of Indian Standards,

indicating moderately active zone.

4.3 LIQUEFACTION:

Liquefaction is the sudden loss of shear strength of the loose fine-grained

sands due to earthquake-induced vibration under saturated conditions.

Subsurface consists of silty gravelly sand with high standard penetration

resistance, followed by dense rock, hence site may be classified as

“Liquefaction unlikely” in earthquake event.

4.4 GROUNDWATER:

Groundwater was encountered in the boreholes at 1.00m depth.

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A viii

5.0 FOUNDATION ANALYSIS AND RECOMMENDATIONS

5.1 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.

5.2 Foundation Type and Depth

All depths given in this report are with reference to the existing

ground surface at the time of our investigation. In case any substantial cutting /

filling operation is to be carried out, the recommendations given in this report

should be reviewed. It should be ensured that all foundations are placed on the

natural soils/ rock and not on fill.

5.3 Shallow Foundations

Bearing capacity analysis for open foundations bearing on soils at site has been

done in accordance with IS: 6403-1981 based on laboratory and field tests.

Settlement analysis has been performed in accordance with

IS: 8009 Part-1-1976. The N values from the Standard Penetration tests

conducted are indicated in the respective Bore-Logs. From The Average of N

values over the significant depth below the foundation, the safe bearing pressure

has been evaluated as per IS 8009 (Part-1) 1976 considering the soil is

predominantly sandy.

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A ix

RECOMMENDED ALLOWABLE BEARING PRESSURE :

Allowable Bearing

Pressure, ton /m2 for a

settlement of

Likely foundation bearing material

Embedment Depth, m

Width (m) / Type of

foundation

25mm

40mm

Recommended Net

Allowable Bearing

Pressure, ton /m2

1.00/ Open 10.00 16.00 10.00

2.00/ Open 8.00 13.00 8.00

3.00/ Open 8.00 13.00 8.00

4.00/ Open 9.00 14.00 9.00

5.00/ Open 8.50 13.50 8.50

Sandy gravelly clay 1.00

6.00/ Open 8.50 13.50 8.50

1.00/ Open 15.00 24.00 24.00

2.00/ Open 12.50 20.00 20.00

3.00/ Open 12.00 20.00 20.00

4.00/ Open 11.50 18.00 18.00

5.00/ Open 11.00 17.50 17.50


6.00/ Open 10.50 17.00 17.00

1.00/ Open 16.00 25.50 25.50

2.00/ Open 13.00 21.00 21.00

3.00/ Open 12.50 20.00 20.00

4.00/ Open 11.50 19.00 19.00

5.00/ Open 11.00 18.00 18.00


6.00/ Open 11.00 17.00 17.00

1.00/ Open 21.00 34.00 34.00

2.00/ Open 17.00 27.00 27.00

3.00/ Open 15.00 24.00 24.00

4.00/ Open 14.00 22.00 22.00

5.00/ Open 13.00 21.00 21.00


6.00/ Open 13.00 20.00 20.00

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A x

Notes: ⇒ It has been found that the water table will rise to founding level from EGL in the peak rainy

season.

⇒ A maximum settlement of 40mm is expected.

⇒ The depth of embedment of foundation has been given from the existing ground level any cutting or filling at that point should be adequately taken care of.

5.4 Excavation Scheme

The temporary excavation is expected to be through the Silty clay / completely weathered Rock.

Description of Strata Recommended Side slopes Excavation Method

silty gravelly clay 1V:2H Conventional Excavators

Highly Weathered rocks 2-3V:1H Drilling / Blasting or needle

breaker

6.0 GENERAL COMMENTS:

The choice of the value for design is a matter of engineering judgment and field assessment of

soil and rock character. After review of the net bearing pressure computed from different

methods, the final value has been selected based on our engineering judgment based on soil and

rock encountered in the limited number of boreholes as reported herein. If any significant

departure from the reported data is noticed during actual construction, the Geotechnical

consultants may be referred for advice.

For Sun-Tech, Ranchi

(Pranay Kumar) Geotechnical Consultant

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A xi

7.References: 1. IS:2720 (part), Grain size Analysis

2. IS:2720(Part XIV), Determination of Density Index

3. IS:2720(Part V), Determination of Liquid & Plastic Limits

4. IS:1498-1970: Classification & identification of soils

5. IS 2720 (Part XV), Determination of Consolidation Properties.

6. IS:2720( Part XI)1975, Triaxial Test (UUT)

7. IS 2720 (Part X) 1973, unconfined compressive strength.

8. IS:1892-1962, site investigation

9. IS 2131-1981, Method for SPT.

10. IS: 2132-1981, Thin walled tube sampling of soils.

11. IS: 1904-1978, Structural Safety of Building Foundations

12. IS:6403-1981, Determination of Bearing Capacity of Foundations

13. IS:8009(Part-1)-1976, Calculation of Settlement of foundations.

14. Arora ,K.R. Soil Mechanics & Foundation Engg.

15. Murthy. VNS, Principles of soil mech. & foundation Engg.

16. Punamia, B.C. Soil Mechanics & foundation Engg.

17. Nayak, M.V., Foundation Design Manual.

18. Brahma, S.P. Soil Mechanics

19. Singh, Alam Modern Geotechnical Engineering

20. IS:2950 (Part-I)-1981 Code of Practice for Raft Foundations

*******************************END OF REPORT****************************

Sun-Tech


33/11kV SUB-STATION AT ODGI, SARGUJA, UNDER RGGVY PACKAGE# SAR-A xii

Annexures `

BOREHOLE LOCATION PLAN

SOIL PROFILE

BORE LOG DATA SHEET

VARIATION OF SPT VALUES WITH DEPTH

DCPT RESULTS

SAMPLE CALCULATIONS

LABORATORY TEST RESULTS

GRAIN SIZE CURVE

TRIAXIAL TEST

Borehole No. : 1 Ground R.L. : 100.000 m

Termination : 5.00 m from EGL

S530910

33/11 kV NEW SUBSTATION AT ODGI

Job No. :

Fig No. :

Sun-Tech

RanchiN Value Curve

Variation of 'N' value with Depth

9

100

32

42

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)



S530910

2


Job No. :

Fig No. :

Sun-Tech

RanchiN Value Curve


15

100

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)



S530910

3


Job No. :

Fig No. :

Sun-Tech

RanchiN Value Curve


18

25

100

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)

Borehole No. : 1/DCPT Ground R.L. : 100.000 m


S530910

4


Job No. :

Fig No. :

Sun-Tech

RanchiDCPT Value Curve

Variation of DCPT value with Depth

10

27

78

79

100

9

9

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)



S530910

5


Job No. :

Fig No. :

Sun-Tech



9

15

17

47

100

11

18

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)



S530910

6


Job No. :

Fig No. :

Sun-Tech



12

100

15

35

0

1

2

3

4

5

6

0 10 20 30 40 50 60 70 80 90 100

Field 'N' value

De

pth

fr

om

E

.G.L

. (m

)

Sun-TechRanchi

U/P 2702 1.00 6.34 51.28 39.38 3.00 52.3 13.7 38.6 - SC 13.60 2.08 2.76 UUT 0.23 24 7 0.004 0.004 - -

P 2103 3.50 7.26 50.20 39.74 2.80 50.3 14.19 36.11 - SC 12.80 2.10 2.64 UUT 0.2 24.5 - - - - -

P 2105 4.50 0.30 61.36 35.54 2.80 40.6 17.65 22.95 - SC 11.85 1.99 2.61 - - - - - - - -

P 2717 4.90 0.00 53.20 37.80 9.00 36.8 17.74 19.06 - SC 12.06 2.02 2.64 - - - - - - - -

U/P 2713 1.50 1.88 58.44 23.68 16.00 43.1 14.5 28.6 - SC 14.31 1.99 2.56 UUT 0.36 20.5 6.5 0.005 0.004 - -

P 2715 3.00 1.32 58.90 39.78 0.00 33.7 15.68 18.02 - SM 13.00 2.04 2.71 UUT 0.01 32 - - - - -

U/P 2707 1.50 0.00 54.34 38.66 7.00 40.8 18.73 22.07 - SC 15.30 2.10 2.74 UUT 0.27 23 7 0.006 0.004 - -

p 2109 3.00 6.50 54.12 35.38 4.00 34.5 17.6 16.9 - SC 11.70 2.03 2.64 - - - - - - - -

p 2109 4.00 0.00 55.64 24.36 20.00 35.6 18.62 16.98 - SC 12.80 2.00 2.71 - - - - - - - -

3. Specific Gravity IS:2720 Part-3-1980 4. Direct Shear Test IS:2720-Part-13 1986 5. Triaxial Test IS:2720 Part-12 1981 6. Consolidation test IS: 2720 Part-15 -1986

7. pH of Soil IS:2720- Part-41 1976 8. Free Swell Index IS: 2720 part-40 1977

Sampling Process: Samples from Bore holes P- SPT Sample, D- Disturbed/ Wash Sample C- Rock Core Sample

BH-1

BH-3

Notes: CONSOLIDATION TEST NOT CONDUCTED DUE TO SANDY NATURE OF SOIL

Abrreviation used : UUT : Triaxial Unconsolidated Undrained, TCU : Triaxial Consolidated Undrained, TCD : Triaxial Consolidated Drained, DS : Direct Shear,

UC : Unconfined Compression, ( R ) : Remoulded sample, U : Undisturbed sample, D : Disturbed sample, P : SPT sample NP: Non Plastic

Notes: Test Methods Referred to: 1. Grain Size Distribution IS:2720 Part-4-1985 2. Liquid, Plastic & Shrinkage Limit IS:2720 Part-5-1985

Co-e

ff. O

f C

om

pre

ssio

n

(Cc)

BH-2

pH

Ch

lori

de (

%)

Su

lfate

(%

)

Init

ial V

oid

rati

o (

eo)

Shear Strength test Chemical TestConsolidation

Test

Gra

vel %

San

d %

Silt

%

Cla

y %

Type o

f te

st

Coh

esio

n (

Kg/cm

2)

An

gle

of

inte

rnal

Fri

cti

on

(D

egre

e)

Cla

ssif

icati

on

(IS

:14

98

-19

70

)

Natu

ral M

ois

ture

Con

ten

t %

Bu

lk D

en

sit

y (

gm

/cc)

Specif

ic G

ravit

y

Pla

sti

cit

y I

ndex

Sh

rin

kage L

imit

%

OWNER: CHHATISGARH STATE POWER DISTRIBUTION COMPANY LTD.

CONSULTANT: POWER GRID CORPORATION OF INDIA LTD.

CONTRACTOR: JYOTI STRUCTURES LTD.

PROJECT: 33/11 kV NEW SUBSTATION AT ODGI, UNDER RGVY

PCAKAGE-SAR-A Proj. Code. :530910

BH

No.

Sam

ple

Type

Sam

ple

Nu

mber

Depth

(m

)

Grain Size Distribution

Liq

uid

Lim

it %

Pla

sti

c L

imit

%

LABORATORY TEST RESULTS ON SOIL SAMPLES Page 1 of 1

Checked/ approved

PARTICLE SIZE DISTRIBUTION CURVE

Job No. : S530910Page 7

Particle Size Distribution CurvesSun-Tech

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10

Particle Size, D (mm)

% F

ine

r th

an

D

BH No. - 1 Depth :1.00m BH No. - 1 Depth : 3.50m BH No. - 2 Depth 1.50m

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10


% F

ine

r th

an

D

BH No. - 2 , Depth :3.00m

PARTICLE SIZE DISTRIBUTION CURVE

Job No. : S530910Page 8

Particle Size Distribution CurvesSun-Tech

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10


% F

ine

r th

an

D

BH No. - 3 Depth :1.50m BH No. - 3 Depth : 3.00m BH No. - 3 Depth 4.00m

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10


% F

ine

r th

an

D

BH No. - 2 , Depth :3.00m

CALCULATION OF ALLOWABLE BEARING PRESSURE BASED ON SPT 'N' VALUES Calculation Sheet

Project: PROPOSED 33/11 kV substation at ODIGA

Location: ODIGA

Customert: JSL

S530910 BH- 1/2/3

Type of Foundation: OPEN/ RAFT

Allowable Settlement: 50 mm

Position of Water Table: AT FOOTING LEVEL

IS:8009(Part-1)-1976

Depth of Width of SPT Design

Foundation Foundation Value

D (m) B (m) N

1.20 1.00 32.00 1.20

1.00 2.00 16.00 1.10

1.00 3.00 17.00 1.07

1.00 4.00 20.00 1.05

1.00 5.00 20.00 1.04

1.00 6.00 20.00 1.03

1.50 1.00 20.00 1.20

1.50 2.00 22.00 1.15

1.50 3.00 24.00 1.10

1.50 4.00 24.00 1.08

1.50 5.00 24.00 1.06

1.50 6.00 24.00 1.05

2.00 1.00 21.00 1.20

2.00 2.00 22.00 1.20

2.00 3.00 24.00 1.13

2.00 4.00 24.00 1.10

2.00 5.00 24.00 1.08

2.00 6.00 24.00 1.07

3.00 1.00 27.00 1.20

3.00 2.00 27.00 1.20

3.00 3.00 27.00 1.20

3.00 4.00 27.00 1.15

3.00 5.00 27.00 1.12

3.00 6.00 27.00 1.10

PROJECT CODE:

Water table correction W' Depth factor df

ALLOWABLE BEARING PRESSURE ton/m2

(qna)

Max. expected settelement

25mm 40mm

The Calculation for Allowable Bearing Pressure is based on

Teng’s Equation :

For a settlement of 25mm of foundation

qna= 3.5(N-3){(B+0.3)2/(4B

2)}df.W’

ref IS:8009-1976 Part-1

0.50

25.73

8.27

41.17

13.24

0.50

13.91

13.56

0.50

0.50

7.91

9.02

12.65

14.44

0.50

0.50

8.69

8.47

0.50 15.08 24.13

0.50 12.64 20.23

0.50 12.23 19.57

0.50 11.41 18.26

0.50 10.94 17.51

0.50 10.64 17.02

0.50 15.97 25.55

0.50 13.19 21.11

0.50 12.60 20.16

0.50 11.68 18.69

0.50 11.15 17.84

0.50 10.80 17.29

0.50 21.29 34.07

0.50 16.66 26.66

0.50 15.25 24.39

0.50 13.95 22.33

0.50 13.21 21.14

0.50 12.73 20.37

Sun-Tech

Ranchi Checked/ Approved

Sun-Tech

Ranchi

Calculation- Sheet

1

2

3

4

5 α

6 2

7 1

1 g/cc

2 %

3 g/cc

4

5

6 degree 20.5 Nc

7 kg/cm2

0.36 Nq

8 W' 0.5 Nγ

Assuming B: (m) 2.00 sc 1.30 dc

L: (m) 2.00 sq 1.20 dq

sγ0.80 dγ

ton/m2

FACTOR OF SAFETY: 3.00

Ultimate net bearing capacity qd: 93.04 ton/m2

qd= cNc. sc .dc.ic + γγγγd(Nq-1).sq.dq.iq + 1/2.B.γγγγ.Ng.sγγγγ.dγγγγ.iγγγγ.W’

Net Bearing Capacity 31.01

The effect of depth factor has not been considered ref. cl. 5.1.2.2 of IS 6403-1981

Effect of water Table 5.39

Void ratio 0.47

Angle of Internal Friction 14.83

Cohesion 6.4

As the soil is cohesionless the analysis for the bearing capacity will have to in pursuant to the Table-3 of IS:6403-1981based on void ratio.

The Void ratio of soil sample 0.47

The condition of soil is dense The bearing capacity will have to be calculated by General Shear Failure Values. Table: 3 of

IS:6403-1981

1.00

GENERAL SHEAR FAILURE

Width of foundation 1.00

Length of foundation 1.00

Specific Gravity 2.56

LABORATORY

Bulk Density of soil 1.99

Natural moisture Content 14.31

Dry Density 1.74

CALCULATION OF BEARING CAPACITY

(IS:6403-1981)

General data: FIELD

Project 33/11 kV SUB-STATION AT ODIGI AT AMBIKAPUR

Location BH-2

Depth of foundation m 1.5

Inclination of Load to vertical in drgrees 0

ISOLATED

-

Structure

RL

RL of Ground water level -

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Ranchi

Calculation- Sheet

1

2

3

4

5 α

6 2

7 1

1 g/cc

2 %

3 g/cc

4

5

6 degree 20.5 Nc

7 kg/cm2

0.36 Nq

8 W' 0.5 Nγ

Assuming B: (m) 2.00 sc 1.30 dc

L: (m) 2.00 sq 1.20 dq

sγ0.80 dγ

ton/m2

FACTOR OF SAFETY: 3.00

CALCULATION OF BEARING CAPACITY

(IS:6403-1981)

General data: FIELD

Project 33/11 kV SUB-STATION AT ODIGI AT AMBIKAPUR

Location BH-2

Structure ISOLATED

RL -

Inclination of Load to vertical in drgrees 0

Depth of foundation m 2

RL of Ground water level -

LABORATORY

Bulk Density of soil 1.99

Natural moisture Content 14.31

Dry Density 1.74

Specific Gravity 2.56

Void ratio 0.47

Angle of Internal Friction 14.83

Cohesion 6.4

Effect of water Table 5.39

As the soil is cohesionless the analysis for the bearing capacity will have to in pursuant to the Table-3 of IS:6403-1981based on void ratio.

The Void ratio of soil sample 0.47

The condition of soil is dense The bearing capacity will have to be calculated by General Shear Failure Values. Table: 3 of

IS:6403-1981

GENERAL SHEAR FAILURE

Width of foundation 1.00

Length of foundation 1.001.00

Ultimate net bearing capacity qd: 99.49 ton/m2

qd= cNc. sc .dc.ic + γγγγd(Nq-1).sq.dq.iq + 1/2.B.γγγγ.Ng.sγγγγ.dγγγγ.iγγγγ.W’

Net Bearing Capacity 33.16

The effect of depth factor has not been considered ref. cl. 5.1.2.2 of IS 6403-1981

Calculation Sheet

25mm 40mm

2.00 0.36 20.50 1.99 31.01 22.00 12.64 20.23

2.00 0.36 20.50 1.99 33.16 22.00 13.19 21.11

WIDTH OF

FOUNDATION

(m)

SHEAR PARAMETERS

c kg/cm2 φφφφ degree γγγγ g/cc

RECOMMENDED ALLOWABLE BEARING PRESSURE- ODIGI SUB-STATION

1.50 20.00

2.00 21.00

Av. SPT N

value over

significant

depth

NET SAFE

BEARING

CAPACITY

ton/m2

NET BEARING

PRESSURE ton/m2 for

settlement of

RECOMMENDED

ALLOWABLE BEARING

PRESSURE ton/m2

DEPTH OF FOUNDATION

(m)

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Ranchi Checked/ Approved

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Documents

Ssir Rggvy Odiga Final