GEO –INVESTIGATION REPORT · FIELD WORK 1. SELECTION OF BORE – HOLES :- 1) 3,Nos number of bore...

CERTIFICATE

This is to certify that the samples are collected from the proposed site OPGC PROPOSED

FOR SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP AREA AT MINES

END. The laboratory tests have been performed under the supervision of qualified personal,

as per the Indian standards and that this report is prepared on the basis of these tests

results and expert experience.

FOR: CADD CONSULTING ENGINEERS PVT. LTD

INTRODUCTION

It is intended to investigate the sub soil strata at the proposed site of OPGC PROPOSED FOR

SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP AREA AT MINES END

OBJECT

The object of the Geo – technical investigation is to:-

Optimize the foundation system, assuring the safe bearing capacity of the soil.

Determination of type, size and depth of foundation.

Analyzing the soil properties.

Suggesting an economically viable of foundation system to be adopted for the proposed

structures.

SCOPE OF WORK It consists of the following:-

Visual reconnaissance of the site.

Field and laboratory investigation.

Engineering judgment based on the current practice.

LIMITATIONS OF INVESTIGATION

The scope of Geo- technical Sub soil investigation is confined within the framework of

agreement and Technical specification with the client. However all the field and laboratory

experiments will be carried out as per the relevant Indian standard code of practice?

THE DETAILED GEO-TECHNICAL INVESTIGATION WORK TO BE CARRIED OUT

CONSISTS OF TWO PARTS.

1. FIELD INVESTIGATION

Location of bore holes.

Boring /drilling up to specified depth below G.L.

Conducting standard penetration test.

Collection UDS samples.

Collecting DS samples.

Determining the depth of water table.

Study of site condition and surroundings.

Taking observation of surrounding structure.

Transportation of all soil samples to laboratory.

2. LABORATORY INVESTIGATION :-

Grain size analysis.

Determination of moisture content.

Unconfined compressive strength.

Determination of Bulk density.

Determination of dry density.

Determination of Void ratio.

Determination of liquid limit.

Determination of plastic limit & plastic index.

Determination of specific gravity.

Determination of shear parameters & settlement calculation.

Determination of DFS test.

LOCATION The proposed site of construction OF OPGC PROPOSED FOR SOIL INVESTIGATION WORK

FOR CONSTRUCTION OF CHP AREA AT MINES END 3

FIELD WORK

1. SELECTION OF BORE – HOLES :-

1) 3,Nos number of bore hole was selected by the Engineer – In – Charge in order to

obtain comprehensive sub-soil data for this site up to specified depth in BH NO-8 TO

10 , below G.L. For detailed laboratory investigation SPT is conducted in suitable

intervals and Disturbed /undisturbed soil samples from the above bore hole were

collected at different levels from as per the instruction of the client with observation of

the ground water level during investigation.

2. BORING :-

2) The sub-soil exploration work at the proposed site was carried out using 150mm

diameter rotary calyx rig boring equipments.

3. STANDARD PENETRATION TESTS :-

3) Standard penetration tests we are conducted in different levels in a continuous manner

using a spilt – spoon sampler. The SPT sampler was lower inside the bore hole after

drilling the required level and is driven by a 65 kg. Hammer with a free fall of 750mm.

In three stages 150mm each and the numbers of blows for each 150mm penetration

was recorded. The details of location and SPT value [N] is shown in bore log data.

4. GROUND WATER TABLE :- 4) During the field work ground water level was observation in bore hole and the level of

ground water table are shown in bore log data.

LABORATORY TESTS The laboratory – tests were conducted on selected SPT / disturbed / undisturbed soil samples collected from the bore holes drilled at the proposed site. The tests include grain size analysis, natural moisture content, D.F.S specific Gravity, liquid limit, plastic limit, plasticity index test and shear test. Particles size distribution tests on representative soil sample were also carried out. The laboratory test confirming to the requirement of I.S and specification were conducted on the soil, sample. The results of all these tests are given in test result sheet separately.

GRAIN SIZE ANALYSIS: The grain size analysis of different soil samples were done as per the requirement of IS: 2720(Pt- IV) 1975 – method of test for soil, Grain size analysis. The details of the test results are shown test result sheet separately in tabular as well as graphically. The result of grain size analysis is used to classify the soil in various depths of bore holes.

NATURAL MOISTURE CONTENT: The natural moisture content were determined as per IS: 2720(Pt –II) – 1973 – Method of test for soil, determination of water content.

DETERMINATION OF BULK DENSITY: The Bulk densities were determined in the laboratory from the UDS samples at different levels and the result are shown separately in tabular form.

DETERMINATION OF DRY DENSITY: The dry density of the UDS/DS samples was determined at the known moisture content and bulk density.

DETERMINATION OF SPECIFIC GRAVITY: The specific gravity of the UDS/DS sample was determined at different levels and the results are shown separately.

DETERMINATION OF VOID RATIO: The void ratios of the UDS/DS samples were determined at different levels and the results are shown separately.

LIQUID LIMIT & PLASTIC LIMIT: [AS PER IS : 2720 Pt – IV] : The liquid and plastic limit of soils were other index properties of soil have also been determined as per the relevant IS code of practice. The liquid and plastic limits of soil samples have been determined in the laboratory and results are shown separately.

DETERMINATION OF SHEAR PARAMETERS: Un consolidated and un drained Tri-axial shear tests were carried out from soil samples collected as per IS : 2720 Pt – IX 1971 with three different cell pressures of 1,2,3kg/sq.cm using Tri – axial shear testing machine and result are shown separately in tabular and graphical manner.

P R E F A C E

The general soil profiles and the geological stratification have been determined

OPGC PROPOSED FOR SOIL INVESTIGATION WORK FOR CONSTRUCTION OF CHP

AREA AT MINES END . The objective of this investigation is to ascertain the

characteristics of Sub-soil to present necessary information for sub-surface. It

was endeavored to study in detail the sub-surface conditions at the project site.

.

The field and laboratory works have been conducted as per relevant Bureau of Indian

standards.

FIELD OPERATIONS In an attempt for optimization in the design of foundation for the proposed building to be

constructed at this site, Geo-technical investigation was done. The entire investigation work had

been divided mainly into two parts (i) Field Work & (ii) Laboratory tests

● Field work determines the types of sub- soil deposit and their characteristics.

● Laboratory tests help in determining the relevant geo-technical properties of the sub-surface

deposited leading to finalization of foundation depth of the structure basing on Bearing capacities

of the foundation strata as well as Influence zone

GROUND WATER TABLE & TERMINATION DEPTH

SL. NO

BORE HOLE NO.

GROUND LEVEL

CHANAGE (M)

TERMINATION DEPTH IN

MTR.

WATER TABLE FROM THE G.L IN

MTR.

1 08 - - 10.0 M 2.3M

2 09 - - 10.0 M 1.8M

3 10 - - 10.0 M 3.3M

BORING & SITU TESTS

Wash boring method was adapted to bores in the soil up to specified depth as mentioned above

below the G.L The SPT were conducted at regular intervals and the samples were brought to the

laboratory with proper identification and labeling standard split spoon sampler was used for

conducting standard penetration test. The number of blows required to drive the sampler for the 1st,

2nd and 3rd 15cm depths were recorded. The total number of blows required to drive the split spoon

sampler due to the free fall of a 663kg. Hammer trough distance of 75cm for the 2nd, and 3rd 15cm

penetration were taken together as the field N-value (penetration resistance) of the soil.

NOTATIONS C Cohesion Ф Angle of internal fraction of soil DS Disturbed Sample UDS Undisturbed Sample NMC Natural Moisture Content NP Non plastic soil G Special gravity G Gravel Content M Slit Content C Clay Content LL Liquid Limit PL Plastic Limit Pl Plasticity index Cc Compression index K Coefficient of permeability UCS Unconfined Compression N SPT Value BH Bore Hole Suffix The Number of Bore Holes Nc,Nq,Nγ Bearing Capacity Factor Sc,Sq,Sγ S hape factors γ Density of soil D Depth of foundation FS Factor of safety Cv Coefficient of consolidation UU Unconsolidated untrained triaxial test CU Consolidated drained triaxial test GC Clayey Gravels GP Poorly Graded Gravels GW Well Graded Gravels SC Clayey Sand SM Silty Sand SW Wel Graded Sand SP Poorly Graded Sand CH Clays of High Plasticity Cl Clays of Intermediate Plasticity CL Clays of Low Plasticity MH Slits of High Plasticity MI Silts of intermediate Plasticity ML Silts of Low Plasticity

GUMUDAENGINEERING PROPERTIES OF SOIL PROJECT: MONOHARPUR (BH NO- 10)

\

Sl.

No

.

Sl.

No

.

so

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am

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co

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cte

d a

t

Typ

e o

f s

am

ple

co

lle

cte

d a

t Grain size analysis Atterberg’s Limits

in %

Fie

ld M

ois

ture

Co

nte

nt

in %

Bu

lk D

en

sit

y in

gm

/cc

.

Dry

D

en

sit

y i

n

gm

/cc

.

Co

he

sio

n (

C)

Kg

f/c

m²

An

gle

of

sh

ea

rin

g

res

ista

nce

(Ø

)

In d

eg

ree

Sp

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Vo

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ati

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D.F

.S.

in %

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alu

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Gro

up

of

so

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Fin

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rav

el in

%

Fin

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%

(10m

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4.7

5m

m)

Co

ars

e s

an

d in

%

(4.7

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o

2.0

0m

m)

Me

diu

m s

an

d

in %

(2m

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0.4

25

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) F

ine

sa

nd

in

%

(0.4

25m

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o

0.0

75

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) S

ilt

& C

lay in

%

(0.0

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) L

iqu

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imit

in

%

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x

in %

1 1.5 SPT 48 7 11 12 22 25 NP

NP

13 - - - - 2.62

- - 36 GM

7.5M TO 8.0M CORE RECOVERY =75 % & RQD = 62 %

8.0M TO 9.0M CORE RECOVERY =81 % & RQD = 78%

9.0M TO 10.0M CORE RECOVERY =82 % & RQD = 78 %

Data for the safe Bearing capacity calculation:

(NonCohesive Soil)

SPT 'N' = 36 (assumed) unconfined compressive strength qu = N/7.5 kg/cm2

= 26 C = qu/2 = 0.00 T/sq.m

Depth = 1.5 M Ø = 35 degree

Width = 2.0 M yt = 1.82 gm/cc

If the Ø 36 General shear failure

condition is to be considered.

LOCAL SHEAR FAILURE CONDITION

Ø' = tan^ (-1)(0.67x tanØ) = 25.0 Degree

C' = 0.67C = 0.00 T/sq.m

AS PER IS :6403-1981,TABLE-1 = 2.62 (from lab test)

Nc' = 20.72 G = 2.62

Nq' = 10.66 q = Yt X Df

Nγ' = 10.88 = 1.82 X 1.50 = 2.73 T/M² `

By = Width X Yt

2.0 X 1.82 = 3.6 T/M²

AS PER IS :6403-1981,TABLE-2

Sc = 1.0 Sq = 1.0 Sy = 1.0

AS PER IS :6403-1981,5.1.2.2

dc = 1.27 dq = 1.13 dγ = 1.13 (Since ø > 10)

AS PER IS :6403-1981,5.1.2.3

ic = 1 iq = 1 iγ = 1 W = 1.0

1.0

Qult = (C NcSc dc ic)+y.d.(Nq-1)Sq dq iq+1/2 By NySy dy Iy W'

= x 20.72 x 1.0 x 1.27 x 1

+ 2.73 x 9.66 x 1.0 x 1.13 x 1

+ 0.5 x 3.6 x 10.88 x 1.0 x 1.13 x 1.0 x 1.0

= 0.0 + 29.8001 + 22.376

= 52.176 T/M²

Qult = 52.18 T/sq.M

3

SBC = 17.39 T/sq.m

0.000

Assuming the Factor of Safety as =

Based on the above 'N' value the following ' Ø ' values are obtained from the fig.1 of the IS: 6403-1981 less soils (C=0).

And for cohesive soils ( Ø =0) the 'c' value is considered from the relation "

Note:- Where ever the test results are not available the same was assumed based on the available values.

Specific gravity of soil at 1.5 m depth (G)

Assuming the depth factor, shape factor and load inclination factors as unity.

Assuming the water table correction factor (W') as the ultimate bearing capacity is calculated as below:

CADD CONSULTING ENGINEERS (P) LTD Bore hole no:-10GEO - TECHNICAL INVESTIGATION & Sheet No :-7

FOUNDATION ENGINEERING.

Corrected 'N'

NAME OF THE WORK : SOIL INVESTIGATION WORKS FOR MONOHARPUR

= 2.0 m = 200 cm

= 1.5 m = 150 cm

= 1.0 m

SPT 'N' VALUE OBSERVED = 36

= 26

Due to over burden pressure

As per IS 8009 part I 1976.

Settlement, For 1 kg/cm2 Read from IS 8009

( part I) 1976 Figure - 9 , P.P-17

= 0.0100 m d = ( WT - D)

= 10.00 mm (After applying W') d/b

= 10 mm Adopted water table correction (W')

Premissable settlement = 25 mm

Therefore Allowable Bearing pressure

= 25 / 10

= 2.500 kg/cm2

= 25.00 T/m2

Water table correction(W')

Corrected N value

NAME OF THE WORK:SOIL INVESTIGATION WORKS FOR MONOHARPUR

ALLOWABLE BEARING PRESSURE FOR 25MM SETTLEMENT

Width of footing (B)

Depth of footing (D)

CALCULATION OF ALLOWABLE BEARING PRESSURE BASED ON SPT 'N' VALUE

CADD CONSULTING ENGINEERS (P) LTD BORE HOLE: 10

GEO - TECHNICAL INVESTIGATION & Sheet No : 1


= 2.0 m = 200 cm

= 1.5 m = 150 cm

= 1.0 m

SPT 'N' VALUE OBSERVED = 36

= 26

Due to over burden pressure

As per IS 8009 part I 1976.

Settlement, For 1 kg/cm2 Read from IS 8009

( part I) 1976 Figure - 9 , P.P-17

= 0.0100 m d = ( WT - D)

= 10.00 mm (After applying W') d/b

= 10 mm Adopted water table correction (W')

Premissable settlement = 40 mm

Therefore Allowable Bearing pressure

= 40 / 10

= 4.000 kg/cm2

= 40.00 T/m2

Water table correction(W')

Corrected N value

NAME OF THE WORK:SOIL INVESTIGATION WORKS FOR MONOHARPUR

ALLOWABLE BEARING PRESSURE FOR 40MM SETTLEMENT

Width of footing (B)

Depth of footing (D)

CALCULATION OF ALLOWABLE BEARING PRESSURE BASED ON SPT 'N' VALUE

CADD CONSULTING ENGINEERS (P) LTD BORE HOLE: 10

GEO - TECHNICAL INVESTIGATION & Sheet No : 1


SUMMARY OF GEOTECHNICAL PARAMETERS & SAFE BEARING CAPACITY

BH

DEPTH

BGL

TYPE

OF

BULK

DENSIT

Y,

SPT-‘N’ ‘N’

CORREC

TION

ARRIVED

ALLOWABLE

BERING

PRESSURE

ALLOWABLE

BERING

PRESSURE

NO (M)SAMPL

Egm/cc VALUE VALUE

C

KG/CM2

Ø

DEGRE

E

SBC T/M²

FOR 25mm

SETTELEMENT

T/M²

FOR 40mm

SETTELEMENT

T/M²

SPT 26

GEO - TECHNICAL INVESTIGATION &

SHEAR

PARAMETERFOOTI

NG IN

M

2X2 361.5 -- -

BH NO :- 10 SHEET NO : 1

NAME OF WORK:- SOIL INVESTIGATION WORKS FOR MONOHARPUR

50.0

CADD CONSULTING ENGINEERS (P) LTD.

10


25.017.4

7.5 M TO 8.0 M

qs = qc x Nj

From laboratory test data

qc = 188 = 1880 T / M2

qs = 1880 x 0 = 188 T / M2

CADD CONSULTING ENGINEERS PVT.LTD.

GEO - TECHNICAL INVESTIGATION &BH NO-10


LOCATION-MONOHARPUR

DEPTH OF FOUNDATION -

AS PER CI .6 OF IS:12070

Where :

qs = Safe Bearing Pressure (gross)

qc = Average UCS of rock cores

Nj = Empirical coefficient

Including FOS 3

SBC is conservatively Restricted to 80 T / M2

for designed purposed.

Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))

δ = Thickness of discontinues (cm)

S = Spacing of discontinues (cm)

Bf = Footing Width

From table 4 of IS :12070 For spacing of discontinues from 30 cm to 100 cm Nj = 0.1

kg / cm2

8.0 M TO 9.0 M

qs = qc x Nj


qc = 216 = 2160 T / M2

qs = 2160 x 0 = 216 T / M2




#REF!



Where :




Including FOS 3



Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))



Bf = Footing Width


kg / cm2

9.0 M TO 10.0 M

qs = qc x Nj


qc = 226 = 2260 T / M2

qs = 2260 x 0 = 226 T / M2




#REF!



Where :




Including FOS 3



Nj = ( 3 + S / Bf ) / (10√(1 + 300 δ / S))



Bf = Footing Width


kg / cm2

BORE HOLE NO -10

SO

AK

ED

UN

SO

AK

ED

7.5m to

8.0m 75% 62% 0.31% 11.7% 5.5 7.8 188 192 87 2.67 2.66 45.5

8.0m

to9.0m 81% 78% 0.31% 11.7% 5.6 9.0 216 222 88 2.67 2.66 45.5

9.0m

to10.0m 82% 78% 0.31% 11.7% 5.9 9.4 226 237 88 2.67 2.66 45.5

NOTE:- Nj = 0.1

qs= S.B.C OF ROCK IN T/M2

qs (qu) X Nj

SBC is conservatively Restricted to 80 T / M2 for designed purposed.

SP

EC

IFIC

GR

AV

ITY

RQ

D %

CO

RE

RE

CO

VE

RY

%

SL

. N

O

SL

AK

E U

DR

AB

ILIT

Y IN

DE

X

(10 m

nts

cycle

)

MO

IST

ER

CO

NT

EN

T (

%)

SO

UN

DN

ES

S

PO

INT

LO

AD

ST

RE

NG

TH

IND

EX

CADD CONSULTING ENGINEERS PVT.LTD.GEO - TECHNICAL INVESTIGATION &

PO

RO

SIT

Y (

MG

/(1+

MG

)X100


SUMMARY OF FOUNDATION DETAILS OF ROCK SAMPLES

LOCATION:-MONOHARPUR

UN

IT W

EIG

HT

OF

RO

CK

(g/c

c)

HA

RD

NE

SS

(H

,SC

AL

E

MO

HS

)

BO

RE

HO

LE

DE

PT

H O

F F

OU

ND

AT

ION

BG

L (

m)

UN

CO

NF

INE

D

CO

MP

RE

SS

ION

ST

RE

NG

TH

OF

RO

CK

IN

T

/M2

(q

s =

qu

* N

J)

CADD CONSULTING ENGINEERS PVT.LTD

GEO-TECHNICAL INVESTIGATION & FOUNDATION ENGINEERING.

Sheet No:1

ANALYSIS OF THE SUB SOIL INVESTIGATION TEST RESULT

LOCATION: - MONOHARPUR

BOREHOLE NO- 10

Borehole no- -10 was sunk up to an average depth of 10.0M the sub soil

strata of the Borehole is given in litho logical form and summarized as

follows.

STRATUM

The top layer up to an average depth up to 3.0m consists of Silt

moorum and from 3.0m to 7.5m depth is D.I rock.

The stratum below an average depth from 7.5 m to 10.0 m is consists

of hard rock .

The strata are moderately medium to very dense compact and low to

medium plasticity.

The SPT value tabulated in bore log data sheet.

The core recovery was observed during investigation and tabulated in bore

log data sheet.

The ground water table was encountered at 3.3 m within boring depth.

FOUNDATION & RECOMMENDATION

Considering the 3 no’s of bore hole and after studying all the engineering

properties it has been decided that depth of foundation can be taken in

suitable depth by digging at least 1.5m inside rock from the original ground

level both for economical point of view and for good structural stability.. But

however the structural designer can adopt higher depth to take advantage of

higher SBC depending upon the load as per decision of designer.

The designer can study the ABP/SBC table for above borehole

and take his own decision as per structural load and position of structure at

the site. The settlement is negligible. Therefore no special care is required for

footing. Single isolated RCC footing can be adopted for framed structure and

for all types of structure.

1. All R.C.C works should be designed as per IS –456-2000

2. Shallow foundation will be designed as per IS: 6403-1981.

3. The groundwater table were encountered and tabulated in Bore log data

in all bore holes.

GEO –INVESTIGATION REPORT · FIELD WORK 1. SELECTION OF BORE – HOLES :- 1) 3,Nos number of bore...

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Transcript of GEO –INVESTIGATION REPORT · FIELD WORK 1. SELECTION OF BORE – HOLES :- 1) 3,Nos number of bore...