BECL_Soil Investigation Report

8/11/2019 BECL_Soil Investigation Report

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BHAVNAGAR ENERGY COMPANY LIMITED,

GANDHINAGAR

FINAL REPORTGeotechnical Investigation work for proposed 2 x 250 MW Lignite

Based Thermal Power Plant in Padva Village, Tal: Ghogha,

Dist: Bhavnagar, State: Gujarat,

VOLUME I

M.K. Soil Testing LaboratoryAHMEDABAD 380 0051.

EMAIL: [email protected], [email protected]


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M.K. Soil Testing Laboratory

CCOONNTTEENNTTSS

SSRR.. NNOO..

CCHHAAPPTT EERR PPAAGGEENNOO..

1. Introduct ion. 1-2

2. Field Invest igat ion 3 11

3. Laboratory Test 12 14

4. Discus sion and Recomme ndatio ns 15 60

4.1 Cool ing Tower

4.2 Reservoir Area

4.3 Switch Yard Area

4.4 Chimney Area

4.5 Turbine Area

4.6 Boi ler Area

4.7 ESP Area

4.8 Administrat ive Bui lding

4.9 Coal Storage Area

4.10 Ligni te Handl ing Uni t

15 18

19 23

24 28

29 33

34 39

40 44

45 49

50 53

54 57

58 60

5. Recommendat ions 61 62

6. Conclusion 63 66

7. Appendix

Typical Calculat ion For Safe Bearing Capaci ty(Chimney Area)

67 71

8. List of Tables:-

1. Observed N Values

2. Swel l ing Propert ies of Soi l

3. Chemical Analysis of Soi l

4. Chemical Analysis of Water

5. Field Permeabi l i ty Test (Constant Head Method)

6. Cycl ic Plate Load Test

7. Stat ic Plate Load Test

8. Consol idat ion Test

9. Electr ical Resist ivi ty Test

10. Reading For Ground Water Table Test

11. Soi l Character ist ics For Boreholes

12. Tr ial Pi t & CBR Test Resul t

72 100

101 103

104

105

106 122

123 128

129 136

137

138 165

166 168

169 334

3 35 - 3 359. Drawings:-


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[ 1 ] INTRODUCTION :

Bhavnagar Energy Company Limited, Gandhinagar proposes Geotechnical

investigation work for proposed installation of 2 x 250MW Lignite Based Thermal Power Plant at

Padva Village, Tal : Ghogha, Dist : Bhavnagar, Gujarat State.

1.1. Scope of Work :

The purpose of the investigations was to determine the sub soil stratification of the soil,

geotechnical information & safe bearing capacity of the soil, so as to provide information that will

assist the structural engineers in the design of the foundations and the relevant works.

The Job was carried out vide your letter no. BECL/Geotechnical-195 dated 28/02/2008

under the guidance and supervision of Tata Consultancy Engineers Engineers, the soil personels

of M. K. Soil Testing Laboratoryand clients engineer. Bhavnagar Energy Company Limited,Gandhinagar has retained the services of Tata Consulting Engineers Ltd as project

consultant.

The scope of this enquiry covers the work of Geotechnical investigations to be carried out

at proposed plant areas.

The scope of services broadly consists of the following.

1. Mobilisation of necessary equipment and personnel to carry out all the works and

demobilization after completing the work.

2. Drilling of boreholes and carrying out necessary field work such as standard

penetration tests, Field Permeability tests, Electrical resistivity tests, Plate load

tests, Cross-hole seismic tests etc. as per the specification of Tata Consulting

Engineers Ltd.

3. Conducting necessary laboratory tests.

4. Preparation and submission of detailed report including recommendations of

foundations and sketches showing generalized soil sub-soil.

The purpose, in brief of the proposed Geotechnical investigations is to ascertain the type

of sub-strata, their characteristics and their suitability for the type of foundations and sub-

structures to be adopted for the type and magnitude to envisaged loading. All the tests that are

required to be carried out for this purpose are conducted. Any additional tests required or specified

by the Engineer were carried out.

Location of boreholes and other field tests shall be as indicated in the drawing NO.

10/7/LP attached in the Appendix of the report.


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This report covers the original work order containing the data of 83 boreholes, 14Nos.

Electrical Resistivity Test, 1 Crosshole test, Cyclic Plate Load Test & Static Plate Load Test and all

the necessary laboratory tests required to furnish the details of specification.

The data of further order containing helipad & colony area will be furnished afterwards in

Vol-II.

1.2 Geology & Geomorphology:

The investigated area is situated at village Padva of Ghogha taluka. The site is about

35 Km. away from Bhavnagar and 13 Km. from Ghogha. The area is connected by road ways with

major cities of Bhavnagar district.

The investigated area isslightly undulating in nature having slope towards sea which is 4

to 5 Km. away from site area The climate of the area is tropicalhaving three main seasons. The

maximum temperature is 440C in the month of May. The average long-term rainfall of Ghogha

taluka is 499 mm. Rainfall is highest in the month of August / September. The Ground water

level of the area is observed at shallow depth, ranges between 6.0 m. to 9.0 m. at the time of

investigation.

Alluvium formation followed by weathered trap formation is observed around the

investigated area. Deccan Trap of Cretaceous to Eocene age is the oldest rock of the area. In

some areas of Ghogha taluka, Ghogha Bed comprising lime stone & conglomerate overlies Gaj

Bed.

SUB-SURFACE GEOLOGY

Geologically the investigated area is covered with alluvial formation, reddish brown, brownish

black clay, lateritic clay, sand, moram, kankar of trap particles.etc. followed by weathered rock.


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[ 2 ]FIELD INVESTIGATIONS :

Field work includes the test to be conducted on field as per relevant IS codes alongwith

the specification of Tata Consulting Engineers Ltd. as detailed below :

(1) Exploratory boreholes using suitable accessories with collection of sample as guided by

client.

(2) Conducting Standard Penetration Test (SPT) at desired intervals alongwith collection of

samples.

(3) Collecting undisturbed samples (UDS) and disturbed samples (DS) at desired interval.

(4) Excavation of trialpits

(5) Conducting static & cyclic plate load test

(6) Carrying out field permeability test (FPT) as directed by the client.

(7) Conducting Electric Resistivity tests (ERT)

(8) Conducting Wave Propagation tests / Cross hole seismic test)

2.1. Boreholes :

The field work includes drilling of total 82 nos. of borehole at the locations specified by

client. The location of borehole is indicated in the layout plan given in the Appendix of report.

Rotary calyx type drilling accessories with TC & Diamond bit was used for boring. The diameter of

the borehole was kept 150mm. The use of diamond bit was introduced with occurrence of hard

rocky strata.

Standard penetration tests were conducted as per IS:2131 in the soil strata at 1.5m

intervals upto 1.5m & 2.0m interval below GL and N values noted. The samples from the split

spoon samples were collected and treated as representative samples for laboratory tests. The

standard penetration test was terminated when the blow court is greater than 100 for 5

consecutive intervals. At some locations SPT were also conducted in weathered / soft tock with

Rock Quality Designation (RQD) less than 25%. The observed values are given vide table no. 1 in

the appendix of the report. The undisturbed samples were collected to obtain the engineering

properties of soil. Water table levels in the boreholes were monitored and recorded and the same

is given in the respective borelogs. Details of boring with soil profile, SPT values along with

sampling details are given in the respective borelogs in the appendix of the report.

2.2. Trialpits :

Total 19 nos. of trialpits were proposed as per the specification but the details of this test

will be furnished with final report.


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2.3. Plate Load Tests :

2.3.1 Static Plate Load Test :

Seven static plate load tests were conducted in accordance with IS:1888:1982 using test

plate of size 60cm x 60cm x 2.5cm (thick). The test was carried out by the reaction i.e. jacking

against a loaded platform by hydraulic jack with pressure gauge arrangements.

A ball and socket arrangement was inserted between girder and jack so as to allow the

plate to rotate while keeping the direction of load vertical throughout. The loads were applied

usually in increments of 0.5 t and were maintained up to time when the rate of settlement got

appreciably steady or to a value of 0.02 mm/min. The settlement was observed by means of two

dial gauges having least count of 0.01mm and travel of 50 mm. After attaining maximum load,

the unloading was done gradually and the test plate was allowed to rebound. When the rate ofrebound became negligible, the dial gauge readings were recorded. The observations are shown

vide table no. 7/1 to 7/8 in the Appendix of the report.

2.3.2 Cyclic Plate Load Test:-

This report includes six cyclic plate load tests conducted in accordance with IS:1888:1982

using test plate of size 60cm x 60cm x 2.5cm (thick). The test was carried out by the reaction i.e.

jacking against a loaded platform by hydraulic jack with pressure gauge arrangements.

A ball and socket arrangement was inserted between girder and jack so as to allow the

plate to rotate while keeping the direction of load vertical throughout. The loads were applied

usually in increments of 0.5 t and were maintained up to time when the rate of settlement got

appreciably steady or to a value of 0.02 mm/min. The settlement was observed by means of two

dial gauges having least count of 0.01mm and travel of 50 mm. After attaining maximum load, the

unloading was done gradually and the test plate was allowed to rebound. When the rate of

rebound became negligible, the dial gauge readings were recorded. The observations are shown

vide table no. 3/1 to 3/6 in the Appendix of the report.

The results are attached in Appendix of the report vide table no. 6/1 to 6/6


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2.4 Field Permeability Test :

Total 19Nos. of field permeability tests were conducted in soil by constant head method as

per IS:5529 (Part-I-1985).

In this method, a hole was drilled or bored up to the level at which the test is to be

performed. The casing is be sunk by drilling and driving or jetting with water and driving, whichever

gives the tightest fir to the casing in the hole. The casing is simultaneously driven as the drilling or

boring of the hole is in progress. After the required level is reached, the hole was cleaned by

means of scooping spoons and bailor. If the hole extends below ground water level, the hole

should be kept full of water while cleaning it (as otherwise, due to water pressure, soil may

squeeze into the bottom of the casing pipe) and should be cleaned by passing air under pressure

by air jetting method.

After the hole is cleaned the test was started by allowing clean water through a metering

system to maintain gravity flow at constant head. The flow was adjusted by the regulating valve in

such a way so as to obtain steady water level in the hole. In the tests above water table, a stable

constant level is rarely obtained and a surging of the level within 20 to 30mm at a constant rate of

flow for about 5 minutes may be considered satisfactory.

For measuring water level or constant water level maintained in the hole during test, the

naked point of the enameled wire of the electric probe was lowered in the hole till it touches the

water level. The observations of the water level at 5 minutes intervals were noted. When three

consecutive readings show constant values, further observations may be stopped and the

constant reading should be taken to the depth of water level. Alternatively, the water reading may

also be taken by means of soundings by masons plumb.

The observations of the test should be recorded suitably. A recommended proforma for

the record of results is given in Appendix of the Report vide table no. 5/1 to 5/17.

The permeability by constant head method (open-end test) should be obtained from the

following relation determined by electrical analogy experiments.

QK = -------------

5.5 rH


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Where

K = coefficient of permeability

Q = constant rate of flow into the hole,

r = interval radius of casing, and

H = differential head of water = H1(gravity head) H1(head loss due to friction)

2.5 Electric Resistivity Test :

The resistivity survey is conducted as per the specification an locations are shown in

location plan. In the geophysical resistivity survey wenner configuration method is used. The main

aim of the present survey is to know engineering properties of the formation and its resistivity at

different depth.

In the wenner four pin method, four electrodes are driven into the earth along a straight

line at equal interval. Current I is passed through the two outer electrodes and the voltage

difference V is observed between the two inner electrodes. The current I flowing into the earth

produces an electric proportional to its density and to the resistivity of the soil. The voltage V

measured between the inner electrodes is therefore, proportional to the field condition. Resistivity

thus will be proportional to the ratio of the voltage to the current.

P = 2 II S V Ohm.m

I

Where P = Resistivity of soil in Ohm.m.

S = Distance between two electrodes in m.

V = Voltage in milli volt.

I = Current in milli Ampere.

At the selected point in the chosen direction i.e. North South, North East South West,

North West South East and East West, four electrodes are driven into the earth up to required

depth along a straight line at equal intervals. The D.C. resistivity meter is placed inthe steady and

level base. The current and potential electrodes are connected to the instrument terminals. By

passing current from the battery box, readings are taken and tabulated in the table. The plotting of

resistivity data are plotted on the double log graph paper and the resistivity of different layers withits thickness is calculated with the help of master curves.

In the investigated area at premark location total 14 vertical electrical sounding (V.E.S.) /

E.R.T. are conducted near boreholes. The resistivity of the sub-surface layers of all the sites is

calculated and data are tabulated in the Table No. 9/1 to 9/14. Plotting of resistivity data is shown

in the drg. No. 10/7/ERT.


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2.6 Wave Propogation Test (Cross hole seismic survey) :

The purpose of geophysical investigations cross-hole seismic survey was to measure P

and S wave velocities to determine the dynamic elastic properties of the subsurface strata. The

scope of work includes cross-hole seismic tests at proposed location. Recordings were to be made

at eight (8) levels up to a depth of 14 m using three collinear boreholes spaced at 3.26m and 3.55

m respectively. Recordings were taken at 1m, 3m, 5m, 7m, 9m, 11m, 13m and 14m.

CROSS-HOLE SURVEY

1. Basic Principle of Cross-Hole Seismic method:

There are two borehole seismic techniques in common use which include cross-hole and

down-hole methods. In horizontal or sub-horizontal strata, cross-hole surveying is more sensitive

in response to the change in soil or rock layers than the down-hole surveying. In cross-hole survey

is more effective in detecting an individual higher or lower velocity band and provide information of

the medium between boreholes.

The crosshole seismic test consists of generation of horizontally traveling P and S waves

at a particular level in one borehole (source hole) and recording their arrivals at same level in two

nearby collinear boreholes (receiving holes). Two receiving holes are preferred for timing accuracy

when true zero time could not be measured. The data recording would be started from the bottom

of the borehole at desired interval upward.

The basic data acquisition system consists of the following:

The following recording parameters were used in the present survey.

RECORDING SYSTEM Galileo (BISON Make)24-CHANNEL SEISMOGRAPH

Main Features 18 bit A/D converter.

IFP amplifier, 126 dB dynamic range.

Selectable sampling rate of 31.25 s to 500 s.

Selectable record length of 16 to 1024 samples.

Frequency range of 3 to 2000 Hz.

Selectable Lowcut, Highcut, Notch filters and automaticanti-aliasig setting.

Recording Range 64 msec

Sampling Rate 125 s

Filters Off

RECEIVER:Downhole Sonde

3-component downhole sensor with Pneumatic clamping.

High-pressure pump.

SEISMIC SOURCE Borehole Hammer (BISON)


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In present study BISON borehole hammer was used as seismic source in source borehole

at desired depths. Total length of this source is 1.2 m with a clamping and impact device at the

center. It further needs 40 cm (approx.) clearance below it for free fall of the weight attached to the

body for downward polarization of shear wave.

2. Receivers :

The receivers used in this crosshole test have appropriate frequency of 10 Hz and

sensitivity characteristics to determine the seismic wave train arrival. The receiving unit consists of

three geophones combined orthogonally to form a triaxial array that is, one vertical and two

horizontal geophones mounted at right angle. In this triaxial arrangement, the vertical component

will be used for S-wave arrival determination and horizontal will be used for P-wave arrival

determination. All the geophones are housed in a single cylindrical container (probe) having

diameter of 75mm and length 30cm. An inflated rubber bladder attached with the borehole

geophone probe was used to hold the probe in firm contact with the sidewall of the borehole.

Battery operated Motorized compressor was used to inflate the bladder for clamping.

3. Recording System:

General layout plan of source and receiver holes is shown in location plan and a

schematic diagram of cross-hole test procedure is shown in Figure.

Fig. 2 Schematic Diagram of Seismic Crosshole Test Procedure


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The recording was made using Galileo (BISON Make) a signal enhancement digital

seismograph. The timing accuracy was made for true zero time by using a Triggering device

attached to the borehole hammer. No filters were applied during data acquisition. The hard copy

prints of the records were taken and saved in hard disc for further processing and interpretation.

Borehole Preparation:

The specifications for borehole preparation are given below:

The preferred method for preparing boreholes for cross hole test incorporates three

collinear boreholes spaced 3 to 5 m apart in a straight line, center-to-center on the ground surface.

In present case source hole to first receiver hole distance was 3.26m and first receiver to second

receiver hole distance was 3.55m. 100 mm boreholes were drilled and 90mm ID PVC casing was

used. The annular space between the casing and the borehole sidewall was filled with grout

mixture using injection grouting. The grout mixture was formulated to approximate closely the

density of surrounding in situ material after consolidation.

A constant center-to-center spacing from top to the bottom of the holes was maintained.

Any minor deviation from verticality of boreholes would result in obtaining ambiguous seismic

velocities and dynamic soil parameters. If the boreholes are not vertical in that case a borehole

deviation survey is to be conducted in all the three-crosshole borings with an instrument capable of

measuring the precise vertical alignment of each hole. Cased and properly grouted boreholes are

essential ensure good quality of data which is to be provided by the client.

4. Data Reduction And Interpretation:

Polarized shear wave trains were added to identify the shear wave arrivals. Fig. 3 shows

the arrival of P & S-waves. Polarised shear waves were stacked for clear identification of S-wave

arrival.

Fig. 3 Polarized Shear Wave for identification of S-wave


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The traces recorded on vertical components were used to determine the travel times of S

waves (Shear Wave) and the traces recorded on the horizontal components were used to

determine the travel times of P-Waves (Compressional Wave). The average velocities for P and S

waves were determined by dividing the distance between source and receiver by their

corresponding travel times at each depth.

Precautions were taken during borehole drilling to keep the boreholes vertical and no

borehole deviation survey was required. Therefore, no correction for borehole deviation was

applied on raw data.

As the time taken by P & S waves through the pipe wall (5mm thick) is negligible as

compare to the time taken by P & S waves from source to receivers. Therefore, no correction is

required for PVC casing and same was not applied on raw data.

2.7 Ground Water Observations :

The depth at which ground water is struck during boring is carefully noted and the depth of

water table has to be ascertained subsequently in the completed borehole by daily observing the

depth for the next six to seven days. Depth of ground water should be observed in wells, if wells

exist in the vicinity. The minimum and maximum ground-water levels should be obtained from local

sources and wells in the area.

The fluctuation in ground water table was noted in order to ascertain the directions of the

natural drainage, and to obtain a clue to the design of intercepting drains to prevent the influx of

ground water on to the site from higher ground. The seasonal variation in the level of water table

its to be noted.

The methods adopted for determining the ground water table in bore holes is as per

IS:6935 and as per the instructions of the Engineer.

In case any variation in the ground water level is observed in any specific boreholes, then

the water level in these bore holes it is recorded daily during the course of the field investigation.Level in nearby wells, streams, etc if any, shall be noted whenever these readings are taken.


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2.7.1 Piezometer / Stand pipe Method :

If so called for, observation wells should be drilled for the purpose of long term studies of

the fluctuation in ground water levels and pressure. A stand pipe of PIezometer were installed in

selected previously drilled or specially drilled bore holes covering bore holes covering the

complete site area. These were be at specified depths as per the specifications and instructions of

the Engineer.

Daily water level readings were recorded immediately following the installations upto the

time of leaving the site. At the end of field work, these installations are to be handed over in

satisfactory working condition to the Engineer without disturbing their position so that the owner

can continue further observations. It is important to install some stand pipes and piezometers prior

to the coming monsoon, in order to record the local effects and variations in the ground water level

during the period.

2.7.2 Piezometer :

Piezometer shall be installed to measure the pore pressures in soil with medium to low

permeability. Piezometers consists of a porous filter attached to the bottom of the UPVC tubing.

The filter is 300mm length and is placed in the bore hole and sealed at top and bottom by grouting.

Hydraulic Plezometers with double line to be used to remove the air trapped in the system.


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[ 3 ]LABORATORY TESTS :

Soil samples (disturbed & undisturbed) collected from boreholes were tested for their

physical and engineering properties & shown vide table no. 2 in the appendix of the report..

3.1 Moisture Content :

Natural moisture content of the soil samples was determined from the collected disturbed

samples using oven drying method, as per IS:2720 (Part II)

3.2 Atterberg Limit Tests :

Atterberg limit tests were conducted on the samples collected from the cohesive layer to

determine the liquid and plastic limits, as per IS: 2720 (Part V).

3.3 Grainsize Analysis :

Grain size analysis by sieve was conducted on selected samples to determine the grain

size distribution. Hydrometer tests were conducted to determine the percentage of clay and silt

fractions in cohesive layers, as per IS:2720 (Part IV).

3.4 Specific Gravity Test :

Specific gravity of the soil grains was determined using specific gravity bottles as per IS:2720

(Part III).

3.5 Direct Shear Test :

Direct shear tests were conducted on the undisturbed samples collected from boreholes

as per IS:2720 (Part XIII).

3.6 Triaxial Shear Test :

Unconsolidated and undrained triaxial shear tests were conducted on the undisturbed

samples collected from boreholes, as per IS:2720 (Part XI) to arrive at the C and values.

3.7 Consolidation Test:-

Consolidation tests were conducted on the undisturbed sample collected from boreholes,

as per IS:2720 (Part XV). The e-log P curves along with compression index, various consolidation

parameters like Cv, mv av etc. are given in the Appendix of the report.


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3.8 Free Swell Index and Swelling Pressure Test:-

These tests are useful for finding swelling characteristics & are conducted as per IS: 2720

Part: 40 & 41 and are tabulated vide table No. 2 in the Appendix of the Report.

3.9 Laboratory testing on Rock samples:

The laboratory testing of rock samples was started after visually inspecting the rock cores.

Following laboratory tests were carried out for determine the physical properties of rock samples.

(a) Water absorption & Porosity

(b) Density of rock

(c) Crushing / Compressive strength of rock

(d) Point load index

For conducting tests the rock specimens were prepared in accordance with IS:9179 using

heavy rigid machine with clamping devise for holding the sample. Electrical overload breakers

were used to prevent the possible damage due to overload, clean water was used for flushing &

cooling machines.

a. Water absorption & Porosity :

Water absorption (W.A.) test was conducted by saturating the rock specimen in water for

atleast 24 hrs & noting the difference in oven dry weight.

Saturated wt wt of oven dry sampleW.A. = ----------------------------------------------- x 100

Oven dry wt.

b. Density :

Density is calculated taking the physical dimension (viz. length, height & dia) & weight

WeightDensity = --------------- (g/Cc)

Volume


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c. Unconfined compressive strength of rock :

Unconfined compressive strength of rock is determined in accordance IS:9143. A loading

machine at sufficient capacity & applying load at required rate was used for this test. The

specimen tested was kept with a moisture content as close to field condition as far as possible.

The length to diameter ratio was kept as 2 & if not possible, correction was applied taking

slenderness standard ratio as 2.

The specimen was kept between two bearing plates wiped clean. The axis was aligned

with the centre of the thrust of the cylindrical seat. A load was applied at a constant rate. The

maximum load was recorded with accuracy causing the failure.

Load at failure

Compressive Strength = -------------------------------- (kg/cm

2

)Cross sectional area


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[ 4 ] DISCUSSION AND RECOMMENDATION :

The whole area under this section is divided as per the field & laboratory data conducted for

different structures like,

Sr.No.

Description Borehole No.

1. Cooling tower area BH No. :50, 51, 52, 47, 48, 49, 64 SPLT :8 & 9

2. Reservation area BH No. :74,75,79,80, FPT :6, 8, 9, 10, 11 ,12TP No. :15,16 & TP-17

3. Switchyard area BH No. :76, 77, 78, 71, 72, 73, 81, 82, 83SPLT No. :4, 5, 6, 7 ERT :6,7,8,9,10,11,12 13 & 14)

4. Chimney area BH No. :30, 31, SPLT :1

5. Turbine area BH No. :59, 60, 61, 62, 63, 65, 66, 67, 68 69, 70CPLT :6, 7, SPLT :2, 3 ERT :1 to 5

6. Boiler area BH No. :45, 46, 54, 55, 56, 57 CPLT :3 & 4

7. ESP area BH No. : 33, 34, 37, 38, 39, 40, 41, CPLT :1 & 2

8. Administrative building BH No. : 35, 36, 27, 28, 42, 43, 58, 59 FPT :4 to 5

9. Local storage area BH No. : 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,20, 21, 22, 23, 24, 25, 26

10. Lignite Handling Unit BH No. : 1 to 5 FPT :1 to 3

The Discussion of the tests along with its recommendations are discussed in following paras :

4.1 COOLING TOWER:

The location details of the field tests in this zone along with its details is shown as under:

Location Water table details Termination detailsSr.No.

Northing Easting

BH No. RL of GL(m.)

Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1 734.8 733.42 BH-47 46.7 15.00 31.70 50 -3.3

2 663.66 699.97 BH-48 47.47 13.40 34.07 30 17.47

3 687.54 779.47 BH-49 44.91 13.00 31.91 40 4.91

4 718.9 857.14 BH-50 47.32 8.40 38.92 35 12.32

5 728.07 932.78 BH-51 47.61 8.00 39.61 36.5 11.11

6 657.7 908.42 BH-52 47.05 7.85 39.20 30 17.05

7 628.54 815.74 BH-64 47.1 7.20 39.90 30 17.1

8 694.51 733.42 SPLT-8 46.95 - - - -

9 694.51 894.86 SPLT-9 47.32 - - - -


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4.1.1 General :

The sub-soil strata in this location is found to consist mainly of reddish grayish coloured

variegated clay with yellowish colour clay intermittent with blackish coloured compact clay. This

layer is extended upto 35m depth. Below 35m depth greenish black coloured highly weathered,

fractured rock basalt is observed in form of crushed material or small boulder like pieces. Average

water level in this zone is around 6.0m to 7.0m.

4.1.2 Soil Stratification :

Laboratory tests conducted on soil samples collected from boreholes are discussed asbelow :

Layer I :

This layer is in stiff to hard consistency with variation in N value as 19 to refusal. The

reddish clayey soil at top shows very high swelling potential. The atterbergs limits & other

laboratory tests along with its variation is shown below :

Properties :

Moisture Content (%) : 15.2 26.5

Dry Density (g/Cc) : 1.37 1.66

Grain size analysis

Gravel (%) : 00 8

Sand (%) : 5 48

Silt & Clay (%) : 52 95

Clay (%) : 25 32

Atterbergs limits

Liquid Limit : 52 78 %

Plasticity Index : 26 52%

Shrinkage Limit : 11 15 %

Shear Properties

Cohesion (kg/cm2) : 0.62 1.85

Angle of friction (degree) : 2 5

Consolidation Properties :

Compression Index Cc : 0.020Co-eff. of vol. change mv : 0.0013

Co-eff. of consolidation Cv : 1.30 x 10-3

Swelling Properties

Free Swell Index (%) : 31 82

Swelling Pressure (kg/cm2) : 0.58 1.66

Type of Soil : CH


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Properties :

Moisture Content (%) : 15.7

Dry Density (g/Cc) : 1.66

Grain size analysis

Gravel (%) : 8 51

Sand (%) : 24 70

Silt & Clay (%) : 19 31

Clay (%) : --

Atterbergs limits



Shrinkage Limit : --

Shear Properties


Angle of friction (degree) : 29.5


Compression Index Cc : -

Co-eff. of vol. change mv : -

Co-eff. of consolidation Cv : -

Swelling Properties

Free Swell Index (%) : -

Swelling Pressure (kg/cm2) : -

Type of Soil : SC / SM / GM

Layer II :

The subsequent layer is found to contain Greenish to reddish black coloured completely

weathered to highly weathered fractured hard & compact rock basalt with variation in CR as nil to

26% and RQD nil to 16%.


20/359

* 18*



Two static plate load test viz. SPLT-8 and 9 were proposed to be conducted in this area.

Due to heavy rain and other site problems. SPLT-9 was not conducted till today on site.

The analysis for SPLT-8 is given as under :

The max. applied load intensity on 60cm x 60m size plate is 100 t/m2with maximum observed

settlement as 5.585mm. No shear or settlement failure was observed at this site.

Hence, the net safe bearing capacity for shear criterion with factor with factor of safety (fs) as 3,

100qns = ---------- = 33.33 t/m

2.

3

Considering settlement criterion and footing size of maximum 3m.

Sp Bp---------- = ---------- for plate load test on clay

Sf Bf

Where,

Sf = Permissible settlement on footing = 0.025m.

Sp = Settlement on plate

Bf = Width of footing = 300cm = 3m

Bp = Width of plate = 60cm = 0.60m.

Substituting all the values

0.6Sp = 0.025 x [ ------- ] = 0.005mm.

3

= 0.005 = 5mm. Corresponding load intensity = 91 t/m2

Hence, allowable bearing pressure = > 91 t/m2.

Hence, from this test net safe bearing pressure can be considered as not less than 33 t/m2.


21/359

* 19*


4.1.4 Recommendation For Net Safe Bearing Capacity :

Type & Size of

Footing(m x m)

Depth Below

Ground Level(m)

Net safe bearing

capacityBased on Shear

(t/m2)

Net safe bearing

capacity based onSettlement

(t/m2)

Recommended Net

safe bearingcapacity

(t/m2)

Square footing1.5m x 1.5m

2.5

3.5

4.5

19

19

24

67

69

73

19

19

24


2.5

3.5

4.5

19

19

24

50

58

62

19

19

24

Square footing3.0m x 3.0m 2.53.5

4.5

1919

24

3226

40

1919

24

Raft foundation6m dia

2.5

4.5

4.5

19

19

24

26

31

35

19

19

24

Note:- Permissible settlement for footing is considered as 25mm & that for raft is considered as 40mm


22/359

* 20*


4.2 RESERVOIR AREA :

The general sub-soil profile at this location is found to consist of reddish grayish coloured,

variegated highly compact clay average water level in this section is 6.0m to 7.0m. Water loss

during drilling is observed as very low indicating low permeable stiff to hard strata.

The location details of the field tests in this zone along with its details is shown as under :

Location (m) Water table details Termination detailsSr.No.

Northing Easting

BH No. RL of GL(m.)

Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1 489.32 699.98 BH-74 48.37 6.80 41.57 33 15.37

2 445.22 781.63 BH-75 46.67 7.10 39.57 30 16.67

3 366.97 713.37 BH-79 48.24 6.60 41.64 30 18.244 366.97 829.56 BH-80 46.6 6.00 40.60 30 16.6

5 476.11 696.03 FPT-6 48.41 - - - -

6 487.53 756.86 FPT-7 47.48 - - - -

7 483.83 830.03 FPT-8 46.34 - - - -

8 435.99 764.27 FPT-9 47.04 - - - -

9 389.08 695.73 FPT-10 48.56 - - - -

10 406.05 829.73 FPT-11 46.42 - - - -

11 358.22 757.48 FPT-12 47.72 - - - -

12 482.02 765.62 TP-15 - - - - -

13 414.19 706.5 TP-16 - - - - -

14 375.82 822.6 TP-17 - - - - -


23/359

* 21*



Laboratory tests conducted on soil samples collected from boreholes are discussed as below :

Layer I :

This layer is in stiff to hard consistency with variation in N value as 12 to refusal. The

reddish clayey soil at top shows very high swelling potential. The atterbergs limits & other


Properties :



Grain size analysis

Gravel (%) : 00 20

Sand (%) : 4 19

Silt & Clay (%) : 62 96

Clay (%) : 21 31

Atterbergs limits



Shrinkage Limit : 11 13 %

Shear Properties




Compression Index Cc : 0.017

Co-eff. of vol. change mv : 0.0014


cm2/sec.

Swelling Properties


Swelling Pressure (kg/cm2) : 0.913

Type of Soil : CI / CH


24/359

* 22*


Properties :



Grain size analysis

Gravel (%) : 10 70

Sand (%) : 78 18

Silt & Clay (%) : 12 40

Clay (%) : -

Atterbergs limits



Shrinkage Limit : -

Shear Properties

Cohesion (kg/cm

2

) : 0.0 0.10Angle of friction (degree) : 28 30.5





Swelling Properties



Type of Soil : SM / SC / GM (occasional pocket)

4.2.3 Field Permeability Test :

Field Permeability Tests no. FPT 7,8,9,10 & 11 were conducted by constant head

method in this zone. The value of co-eff of permeability k derived from these tests is as below :

Location

BH No. East North

RL of GL

(m.) Depth K (cm/sec)

FPT-7 756.86 487.53 47.48 6.0 1.44 x 10-3

FPT-8 830.03 483.83 46.34 4.20 1.19 x 10-3

FPT-9 761.27 435.99 47.04 7.00 8.27 x 10-4

FPT-10 695.73 389.08 48.17 5.50 8.42 x 10-4

FPT-11 829.73 406.05 46.42 5.50 9.26 x 10-4

This shows k value varies from 1.19 x 10-3

to 9.6 x 10-4

cm/sec indicating medium permeability.


25/359

* 23*


4.2.4 Recommendation for Net Safe Bearing Capacity :

Type & Size ofFooting(m x m)

Depth BelowGround Level

(m)

Net safe bearingcapacity

Based on Shear(t/m

2)

Net safe bearingcapacity based on

Settlement(t/m

2)

Recommended Netsafe bearing

capacity(t/m

2)

Wall footing1.5m wide

2.5

3.5

10

13

51

58

10

13


2.5

3.0

10

13

39

42

10

13


2.5

3.5

10

13

26

30

10

13


26/359

* 24*


4.3 SWITCHYARD AREA :


Location Water table details Termination detailsSr.

No. Northing Easting

BH No. RL of GL

(m.) Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1 446.46 445.81 BH-71 47.07 8.85 38.22 30 17.07

2 446.46 513.81 BH-72 47.57 9.15 38.42 19 28.57

3 446.47 597.65 BH-73 51.46 15.40 36.06 30 21.46

4 387.78 445.81 BH-76 47.62 6.30 41.32 30 17.62

5 387.78 513.81 BH-77 48.12 6.65 41.47 30 18.12

6 387.79 597.65 BH-78 50.16 6.40 43.76 30 20.16

7 321.25 445.81 BH-81 48 5.85 42.15 13.5 34.5

8 321.25 513.81 BH-82 48.36 6.20 42.16 30 18.36

9 321.25 597.65 BH-83 51.25 6.40 44.85 30 21.25

10 427.59 465.33 SPLT-4 47.44 - - - -

11 427.59 580.95 SPLT -5 49.75 - - - -

12 340.62 465.34 SPLT -6 48.1 - - - -

13 340.62 580.95 SPLT -7 49.88 - - - -

14 428.74 455.14 ERT-6 47.5 - - - -

15 428.72 523.14 ERT-7 47.68 - - - -

16 428.74 597.65 ERT-8 50.57 - - - -

17 370.06 455.14 ERT-9 47.8 - - - -

18 370.04 523.14 ERT-10 48.31 - - - -

19 370.06 597.65 ERT-11 50.28 - - - -

20 333.26 455.14 ERT-12 48 - - - -

21 333.26 523.14 ERT-13 48.51 - - - -

22 333.28 597.65 ERT-14 50.9 - - - -

4.3.1 General :

The sub-soil strata in this location is found to consist mainly of reddish grayish coloured

variegated clay with yellowish colour clay intermittent with blackish coloured compact clay. This

layer is extended upto 35m depth. Below 35m depth greenish black coloured highly weathered,

fractured rock basalt is observed in form of crushed material or small boulder like pieces. Average

water level in this zone is around 8.0m to 9.0m.


27/359

* 25*




Layer I :

This layer is in stiff to hard reddish consistency with variation in N value as 3 to refusal.

The reddish clayey soil at top shows very high swelling potential. The atterbergs limits & other


Properties :



Grain size analysis

Gravel (%) : 00 4

Sand (%) : 3 13

Silt & Clay (%) : 84 97

Clay (%) : 27 33

Atterbergs limits



Shrinkage Limit :

Shear Properties





Co-eff. of vol. change mv : 0.0014 cm2/kg


cm2/sec.

Swelling Properties

Free Swell Index (%) :

Swelling Pressure (kg/cm2) : --

Type of Soil : CH


28/359

* 26*


Properties :



Grain size analysis

Gravel (%) : 0 28

Sand (%) : 33 71

Silt & Clay (%) : 18 40

Clay (%) : -

Atterbergs limits



Shrinkage Limit : -

Shear Properties

Cohesion (kg/cm

2

) : 0.08 0.06Angle of friction (degree) : 28 - 29





Swelling Properties



Type of Soil : SM / SC

Layer II :



32% and RQD nil to 22%, except boreholes BH 71, BH 73 and BH 78 where any soils are

observed upto termination depth of 30.0m.


29/359

* 27*



Four static plate load test viz. SPLT-4,5,6 & 7,8 and 9 were proposed to be conducted in

this area. Due to heavy rain and other site problems. SPLT-4 was not conducted till today on site.


The max. applied load intensity on 60cm x 60m size plate is 83.33 t/m2with maximum observed

settlement as 9.240mm. No shear or settlement failure was observed at this site.


83.33qns = ---------- = 27.78 t/m

2. Say 28 t/m

2.

3

Considering settlement criterion and footing size of max. 3m.


Sf Bf

Where,

Sf = Permissible settlement on footing = 0.025m. (as required by the party)





0.6Sp = 0.025 x [ ------- ] = 0.005m.

3

= 0.005m = 5mm. Corresponding load intensity = 42.2 t/m2

Hence, allowable bearing pressure = > 42 t/m2.

Hence, from this test net safe bearing pressure can be considered as not less than 28 t/m2.

The analysis of other test is also made is same manner & is listed. The graphs are shown in the

Appendix.


30/359

* 28*


Location (m)Test No.

Northing(m)

Easting(m)

RL of GL(m)

SBC from ShearCriterion (t/m

2)

Safe BearingCapacity from

Settlement Criterion(t/m

2)

SPLT - 5 427.59 580.95 49.75 22 67

SPLT 6 340.62 465.34 48.1 28 53

SPLT 7 340.62 580.95 49.88 28 42

4.3.4 Electrical Resistivity Test :

LOCATION RESISTIVITY ( Ohm.m. )/ THICKNESS ( m.)

SR NO ERTNO.

East (m) North (m) P1 / h1 P2 / h2 P3 / h3

GEOLOGY

1. 6 455.14 428.74 7.2 / 1.07 7.2 / -

2. 7 523.14 428.72 2.4 / 1.05 5.4 / -

3. 8 597.65 428.74 20.0 / 1.06 20 / 3.30 3.0 / -

4. 9 455.14 370.06 39 / 1.07 11.7 / -

5. 10 523.14 370.04 2.0 / 1.09 5.0 / -

6. 11 597.65 370.06 11.3 / 1.07 11.3 / 3.75 2.26 / -

7. 12 455.14 333.26 28 / 1.07 11.2 / -

8. 13 523.14 333.26 1.35 / 1.07 6.75 / -

9. 14 597.65 333.28 11.6 / 1.08 11.6 / 2.38 3.48 / -

Alluvial

formation,

clay, lateritic

clay kankar,

trap

particles.

moram etc.

followed by

weathered

rock.




(m)


Based on Shear(t/m

2)


Settlement(t/m

2)


capacity(t/m

2)


2.5

3.0

11

16

103

110

11

16


2.5

3.0

11

16

77

86

11

16


2.5

3.0

11

16

52

58

11

16


31/359

* 29*


4.4 CHIMNEY AREA :


Location (m) Water table details Termination detailsSr.

No.

Northing Easting

BH No. RL of GL

(m.)

Depth

(m.)

R.L.

(m.)

Depth

(m.)

R.L.

(m.)

1 868.8 521.7 BH-30 44.69 10.00 34.69 30 14.69

2 868.8 578.7 BH-31 44.89 10.50 34.39 35 9.89

3 878.8 550.2 SLPT-1 44.48 - - - -

4.4.1 General :

The sub-soil strata in this location is found to consist grayish white coloured variegated

clay with yellowish coloured clay upto around 20.0m. Below 20.0m depth grayish coloured, highly

fractured weathered rock basalt is observed in form of crushed material or small boulder like

pieces. Average water level is 10m below GL.


32/359

* 30*




Layer I :

This layer is in stiff to hard reddish consistency with variation in N value as 14 to 92. The

reddish clayey soil at top shows very high swelling potential. The Atterbergs limits & other


Properties :



Grain size analysis

Gravel (%) : 00

Sand (%) : 3 12

Silt & Clay (%) : 88 97

Clay (%) : 25 32

Atterbergs limits



Shrinkage Limit : 11 12%

Shear Properties







cm2/sec.

Swelling Properties



Type of Soil : CH


33/359

* 31*


Properties :



Grain size analysis

Gravel (%) : 15 28

Sand (%) : 49 63

Silt & Clay (%) : 18 27

Clay (%) :

Atterbergs limits

Liquid Limit : Non plastic

Plasticity Index : Non plastic

Shrinkage Limit : Due to conducted due to saneShear Properties

Cohesion (kg/cm2) : 0.00





Co-eff. of consolidation Cv : -.

Swelling Properties



Type of Soil : SM

Layer II :



32% and RQD nil to 21%. Only in BH 31.


34/359

* 32*



One static plate load test viz. SPLT-1 was proposed to be conducted in this area.



settlement as 23.765mm. No shear or settlement failure was observed at this site. But the large

settlement was observed as load increased from 24t to 30t. Looking to the nature of graph

tangents were drain to find out the failure point i.e. at 18.4t load.


18.4

qns = ------------- = 17 t/m2

. (Considering load corresponding to 12.5mm settlement)0.6 x 0.6

15.2= ------------- = 14 t/m

2. (By tengement method)

0.36 x 3(Considering load 12.5mm settlement)



Sf Bf

Where,






0.6

Sp = 0.025 x [ ------- ] = 0.005m.3

= 0.005m = 5mm

Corresponding the graph of load v/s settlement, corresponding load against 5mm settlement, is

11.6 giving load intensity 32.2 t/m2.

Hence, allowable bearing pressure = 32 t/m2.

Hence, from this test net safe bearing pressure can be considered as 17 t/m2.


35/359

* 33*





(m)


Based on Shear(t/m

2)


Settlement(t/m

2)


capacity(t/m

2)

Square foundation3.0m x 3.0m

3.5

4.0

19

21

46

49

19

21


3.5

4.0

19

21

29

37

19

21

Circular raft width6.0m

3.5

4.0

19

21

20

25

19

21


36/359

* 34*


4.5 TURBINE AREA :



Northing(m.)

Easting(m.)

BH No. RL of GL(m.)

Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1600.03 444.12 BH-59 46.03 10.50 35.53 40 6.03

2 600.03 493.62 BH-60 45.95 10.70 35.25 40 5.95

3 600.03 545.15 BH-61 46.62 11.20 35.42 40 6.62

4 600.04 592.52 BH-62 48.06 10.30 37.76 30 18.06

5 601.42 644.51 BH-63 48.94 10.15 38.79 30 18.94

6 547.64 478.42 BH-65 46.68 8.10 38.58 30 16.68

7 558.42 532.35 BH-66 46.95 8.00 38.95 30 16.95

8 558.45 589.4 BH-67 48.47 8.70 39.77 40 8.47

9 513.56 485.71 BH-68 47 9.20 37.80 35 12

10 517.18 539.42 BH-69 47.39 8.90 38.49 30 17.39

11 514.54 590.33 BH-70 51.55 9.00 42.55 30 21.55

12 609.56 537.88 CPLT-6 46.65 - - - -

13 582.01 628.63 CPLT-7 49.2 - - - -

14 513.27 505.78 SLPT-2 47.25 - - - -

15 529.13 576.15 SLPT-3 48.3 - - - -16 584.3 445.36 ERT-1 46.38 - - - -

17 584.3 546.39 ERT-2 47.15 - - - -

18 584.3 605.68 ERT-3 49.65 - - - -

19 516.2 522.71 ERT-4 47.23 - - - -

20 530.27 599.98 ERT-5 51.38 - - - -

4.5.1 General :

In general the sub-soil stratification in this zone is found to contain reddish grayishcoloured, variegated clay with intermittent bluish coloured compact clay upto 20.0m depth. Below

20m. completely weathered, fractured basalt was encountered & is recovered in crushed form.

This layer is extended upto max. 40.m depth of termination crushed form. This layer is extended

upto max. 40.0m depth of termination.


37/359

* 35*




Layer I :

This layer is in stiff to hard reddish consistency with variation in N value as 5 to refusal.

Borehole No. 65 & 70 shows comparatively loose condition. The reddish soil at top very high

swelling potential. The atterbergs limits & other laboratory tests along with its variation is shown

below :

Properties :



Grain size analysis

Gravel (%) : 00

Sand (%) : 3 30

Silt & Clay (%) : 58 98

Clay (%) : 28 34

Atterbergs limits



Shrinkage Limit : 13 16%

Shear Properties







cm2/sec.

Swelling Properties


Swelling Pressure (kg/cm

2

) : 0.68Type of Soil : CI/CH


38/359

* 36*


Properties :

Moisture Content (%) :

Dry Density (g/Cc) :

Grain size analysis

Gravel (%) : 00 - 58

Sand (%) : 18 71

Silt & Clay (%) : 2 48

Clay (%) :

Atterbergs limits

Liquid Limit : 40 %


Shrinkage Limit :

Shear PropertiesCohesion (kg/cm

2) : 0.02 0.06

Angle of friction (degree) : 28





Swelling Properties


Swelling Pressure (kg/cm2

) : -

Type of Soil : SM / SC / GM / GC

Layer II :

The underlying layer is found to contain highly to completely weathered, fractured basalt

having core recovery varying from nil to 46% & RQD as nil to 31%.


39/359

* 37*



Four static plate load test viz. SPLT- 2 and 3 were proposed to be conducted in this area.



settlement as 9.605m. No shear or settlement failure was observed at this site.


83.33qns = ---------- = 27.78 t/m

2. Say 28 t/m

2.

3



Sf Bf

Where,






0.6Sp = 0.05 x [ ------- ] = 0.01m.

3

= 0.010m = 10mm which is greater than max. observed settlement

Hence, safe allowable bearing pressure = > 83 t/m2.

Hence, from this test net safe bearing pressure can be considered as greater than 28 t/m2.

Similarly analysis for SPLT-3 is made & as presented below :

LocationTest No.

Northing(m)

Easting(m)

RL of GL Depth(m.)

SBC fromShear Criterion

(t/m2)

Safe BearingCapacity from

Settlement Criterion(t/m

2)

SPLT-2 513.27 505.78 47.25 3.5 28 83

SPLT-3 529.13 576.15 48.3 3.5 28 83


40/359

* 38*



Total two nos. of cyclic plate load tests viz. PLT-6 & 7 were conducted to find out dynamic

soil parameters. From graph of elastic settlement V/S load and in accordance with IS 5429, a

dynamic property for CPLT-7 is derived as under:-

CPLT-6 could not be conducted on site due to heavy rain & is pending

From graph of load V/S elastic settlement

*Co.eff of elastic uniform compression Cup = 10 .0.26 x 0.36

= 106.83 Kg/cm3

Cufoundation having area > 10m2Cuf= Cup Ao/A1

= 106.83 x 0.6 x 0.610

= 20.27 Kg/cm2

* The Elastic modulus E = (1 - 2). A. Cu.1.13

Where, = poisons ratio 0.47 = (1 0.472). 100000 x 20.271.13

= 4419.4 Kg/cm2. Say 4410 kg/cm

2.

*The shear modulus G = E/2(1+) = 441955___ = 1503.2 Kg/cm2

2(1+0.47)

* Co.eff of elastic uniform shear C= Cu/2 = 10.135 Kg/cm3

* Co.eff of elastic uniform shear C= 0.75 Cu = 15.20 Kg/cm3

* Co.eff of elastic uniform compression C= 1.73cu = 35.06 Kg/cm3

Hence, the dynamic shear modulus G for this sector is 1503.2 kg/cm2.

Elastic modulus is 4410 kg/cm2& Cu as 20.27 kg/cm

3.


41/359

* 39*


4.5.5 Elastic Resistivity Test :

Total five nos. of Electrical resistivity tests viz. ERT 1 to ERT-5 were conducted at this site.

The interpreted resistivity results are tabulated below :

LOCATION RESISTIVITY ( Ohm.m. )/ THICKNESS ( m.)

SR NO ERTNO.

East (m.) North (m.) P1 / h1 P2 / h2 P3 / h3

GEOLOGY

1 1 445.36 584.3 10.75 / -

2 2 546.39 584.3 6.0 / -

3 3 605.68 584.3 7.05 / -

4 4 522.71 516.2 7.5 / -

5 5 599.98 530.27 11.2 / -

Alluvialformation, clay,

lateritic claykankar, trap

particles.moram etc.followed byweathered

rock.

4.5.6 Recommendation Safe Bearing Capacity :



(m)


Based on Shear(t/m

2)


Settlement(t/m

2)


capacity(t/m

2)


3.5

4.0

5.0

15

17

17

35

37

39

15

17

17Square foundation2.0m x 2.0m

3.5

4.0

5.0

15

17

17

25

27.5

30

15

17

17


3.5

4.0

5.0

15

17

17

18

19

22

15

17

17

Circular footing6.0m dia

3.5

4.0

5.0

15

17

17

16

22

27

15

17

17


42/359

* 40*


4.6 BOILER AREA :



Northing(m.)

Easting(m.)

BH No. RL of GL(m.)

Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1 725.83 499.97 BH-45 45.08 11.35 33.73 40 5.08

2 725.83 599.97 BH-46 47.34 10.90 36.44 30 17.34

3 685.47 499.97 BH-54 45.76 10.30 35.46 30 15.76

4 685.47 599.97 BH-55 47.72 10.85 36.87 30 17.72

5 651.05 499.97 BH-56 45.93 9.30 36.63 30 15.93

6 651.05 599.97 BH-57 48.63 11.20 37.43 30 18.63

7 669.27 478.88 CPLT-3 45.34 - - - -

8 700.04 618.02 CPLT-4 48.01 - - - -

4.6.1 General :

In general the sub-soil stratification in mainly found to contain reddish grayish coloured

variegated loose clay upto around 10.0m depth. Below 10m, blackish coloured fine to medium

grained gravels upto 20.0m depth. Below 20m depth, grayish black coloured, highly weathered &

fractured basalt is recovered upto 30.0m depth water table is about 1.0m below GL.


43/359

* 41*



Laboratory tests conducted on soil samples collected from boreholes are discussed as

below :

Layer I :

This layer is in stiff to hard reddish consistency with variation in N value as 15 to refusal. In

this zone BH-54 shows very weak zone having silty sand with medium dense consistence. The

reddish soil at top very high swelling potential. The atterbergs limits & other laboratory tests along

with its variation is shown below :

Properties :



Grain size analysis

Gravel (%) : 00 10

Sand (%) : 6 42

Silt & Clay (%) : 58 96

Clay (%) : 21 31

Atterbergs limits



Shrinkage Limit : 13%

Shear Properties







cm2/sec.

Swelling Properties



Type of Soil : CH/CI


44/359

* 42*


Properties :

Moisture Content (%) : 1.47

Dry Density (g/Cc) : 2.12

Grain size analysis

Gravel (%) : 00 - 25

Sand (%) : 28 75

Silt & Clay (%) : 19 60

Clay (%) :

Atterbergs limits

Liquid Limit : Non plastic

Plasticity Index : Non plasticShrinkage Limit :

Shear Properties

Cohesion (kg/cm2) : 0.00

Angle of friction (degree) : 28





Swelling Properties



Type of Soil : SM / SC / ML

Layer II :

This layer is found to contain greenish black coloured, highly fractured, weathered rock

having core recovery varying from 21 to 61% and Rock quality designation as nil to 52%.


45/359

* 43*



Total two nos. of cyclic plate load tests viz. CPLT-3 & 4 were conducted to find out

dynamic soil parameters. From graph of elastic settlement V/S load and in accordance with IS

5429, a dynamic property for CPLT-4 is derived as under:-


*Co.eff of elastic uniform compression Cup = 10 .0.43 x 0.36

= 64.6 Kg/cm3


= 64.6 x

0.3610

= 12.26 Kg/cm2


* Where, = poisons ratio 0.44 = (1 0.442).10000 x 12.26

1.13

= 2573 Kg/cm2.

*The shear modulus G = E/2(1+) = 2573___ = 893.40 Kg/cm2

2(1+0.44)



* Co.eff of elastic uniform compression C= 1.73cu = 21.21 Kg/cm3

Similarly the all parameters are derived and summarized as under :

LocationLocation

North(m.)

East(m.)

RLofGL

Depth(m)

Cu(Kg/cm

3C

(Kg/cm3

C(Kg/cm

3C

(Kg/cm3

Shearmodulus

G

(kg/cm3)

ElasticModulus

E (kg/cm2)

CPLT-3 669.27 478.88 - 3.5 17.57 8.8 30.4 13.2 1377 3963

CPLT-4 700.04 618.02 - 3.5 12.26 6.1 21.21 9.2 893 2573

From these tests, the recommended values for Boiler area are E as 3200 kg/cm2, Cu as 15 kg/cm

3

and G as 1135 kg/cm2.


46/359

* 44*





(m)


Based on Shear(t/m

2)


Settlement(t/m

2)


capacity(t/m

2)


3.5

4.0

5.0

17

20

20

42

46

49

17

20

20


3.5

4.0

5.0

17

20

20

34

39

44

17

20

20


47/359

* 45*


4.7 ESP AREA :



Northing(m.) Easting(m.)

BH No. RL of GL(m.)

Depth(m.) R.L.(m.) Depth(m.) R.L.(m.)

1 818.77 513.93 BH-33 44.69 13.10 31.59 30 14.69

2 818.77 600 BH-34 45.73 15.00 30.73 30 15.73

3 805.34 485.64 BH-37 44.23 15.00 29.23 30 14.23

4 753.63 475.2 BH-38 44.61 14.85 29.76 19 25.61

5 777.8 514.01 BH-39 45.45 15.30 30.15 30 15.45

6 777.8 586.4 BH-40 46.8 15.00 31.80 30 16.8

7 777.8 625.2 BH-41 46.37 15.50 30.87 30 16.37

8 777.72 490.6 CPLT-1 44.73 - - - -

9 807.04 600 CPLT-2 45.99 - - - -

4.7.1 General :

In this zone BH-33, 40, 34 & 41 shows reddish to grayish coloured variegated clay with

expansive nature. Whereas remaining boreholes i.e. BH-38,39 & 37 shows top 15m. loose

variegated clay followed by grayish black coloured highly weathered fractured sound rock basalt.

Water table is at 15.0m below GL.


48/359

* 46*




Layer I :

This layer is in stiff to hard reddish consistency with variation in N value as ---. The reddish

soil at top very high swelling potential. The atterbergs limits & other laboratory tests along with its

variation is shown below :

Properties :



Grain size analysis

Gravel (%) : 00 14

Sand (%) : 1 17

Silt & Clay (%) : 58 99

Clay (%) : 24 34

Atterbergs limits



Shrinkage Limit : 9 12

Shear Properties




Compression Index Cc : 0.013 0.017



cm2/sec.

Swelling Properties


Swelling Pressure (kg/cm

2

) : 0.92Type of Soil : CH


49/359

* 47*


Properties :

Moisture Content (%) : -

Dry Density (g/Cc) : -

Grain size analysis

Gravel (%) : 00 - 21

Sand (%) : 38 66

Silt & Clay (%) : 28 46

Clay (%) : -

Atterbergs limits

Liquid Limit : 36 52

Plasticity Index : 12 28Shrinkage Limit :

Shear Properties

Cohesion (kg/cm2) : -

Angle of friction (degree) : -





Swelling Properties



Type of Soil : SM / SC

Layer II :

This layer is found to contain greyish black coloured, highly fractured, weathered rock

having core recovery varying from nil to 45% and Rock quality designation as nil to 22%.


50/359

* 48*



Total two nos. of cyclic plate load tests viz. CPLT-1 & 2 were conducted to find out

dynamic soil parameters. From graph of elastic settlement V/S load and in accordance with IS

5249, a dynamic property for CPLT-1 is derived as under:-

CPLT-6 could not be performed on site due to heavy rains.


*Co.eff of elastic uniform compression Cup = 10 .x 1 .0.36 0.48

= 57.87 Kg/cm3


= 67.87 x 0.6 x 0.610

= 10.98 Kg/cm2


* Where, = poisons ratio 0.44 = (1 0.442).60 x 60 x 57.87

1.13

= 2477.86 Kg/cm2.

*The shear modulus G = E/2(1+) = 2477.86___ = 860.37 Kg/cm2

2(1+ 0.44)



* Co.eff of elastic uniform compression C= 1.73cu = 19 Kg/cm3

Hence, the dynamic properties for this area is recommended as Cu 10.98 kg/cm3. E as 2477

kg/cm2& G as 860 kg/cm

3.


51/359

* 49*




Depth BelowGround Level(m)

Net safe bearingcapacityBased on Shear

(t/m2)

Net safe bearingcapacity based onSettlement

(t/m2)

Recommended Netsafe bearingcapacity

(t/m2)


3.5

4.0

5.0

10

18

20

60

64

68

10

18

20


3.5

4.0

5.0

10

18

20

47

49

49

10

18

20


3.5

4.0

5.0

10

18

20

34

39

41

10

18

20


52/359

* 50*


4.8 ADMINISTRATIVE BUILDING :



Northing(m.)

Easting(m.)

BH No. RL of GL(m.)

Depth(m.)

R.L.(m.)

Depth(m.)

R.L.(m.)

1 845.02 207.45 BH-27 44.95 11.90 33.05 30 14.95

2 844.98 266.76 BH-28 44.98 13.00 31.98 30 14.98

3 811.97 208.8 BH-35 45.19 15.50 29.69 30 15.19

4 784.29 265.03 BH-36 4.52 14.45 -9.93 30 -25.48

5 711.96 193.85 BH-42 45.93 9.40 36.53 30 15.93

6 697.29 254.69 BH-43 45.93 10.70 35.23 30 15.93

7 632.78 398.16 BH-58 45.03 11.40 33.63 40 5.03

8 600.03 444.12 BH-59 46.03 10.50 35.53 40 6.03

4.8.1 General :

In general overall strata in this area is found to consist of brownish coloured clayey sand.

Underlained by greyish black coloured completely to highly weathered crushed fractured rock

basalt. Water table is observed at around 13m to 15m depth below GL. BH-27 is found very weak

in this zone.


53/359


54/359

* 52*


Properties :



Grain size analysis

Gravel (%) : 0.0 2.0

Sand (%) : 2 8

Silt & Clay (%) : 62 97

Clay (%) : 28 36

Atterbergs limits


Plasticity Index : 27 38

Shrinkage Limit :

Shear Properties







Swelling Properties



Type of Soil : CH

Layer II :

This layer is found to contain grayish black coloured, highly fractured, hard basalt rock

having core recovery varying from nil to 45% and Rock quality designation as nil to 36%.


55/359

* 53*





(m)


Based on Shear

(t/m

2

)


Settlement

(t/m

2

)


capacity

(t/m

2

)Square foundation1.5m x 1.5m

2.0

3.0

14

22

12

17

12

17


2.0

3.0

15

23

10

14

10

14

Note : This zone contains silty sand and for settlement use of N-value is made as per IS:8009. BH-27 is

very loose through out the drilled depth and hence should be treated carefully.


56/359

* 54*


4.9 COAL STORAGE AREA :



Northing(m.) Easting(m.)

BH No. RL of GL(m.)

Depth(m.) R.L.(m.) Depth(m.) R.L.(m.)

1 1285.69 369.53 BH-6 42.52 12.00 30.52 30 12.52

2 1324.13 653.43 BH-7 42.25 12.15 30.10 30 12.25

3 1277.15 564.96 BH-8 40.42 11.50 28.92 30 10.42

4 1252.45 462.06 BH-9 40.3 11.75 28.55 30 10.3

5 1179.02 399.1 BH-10 41.66 12.00 29.66 30 11.66

6 1138.52 584.32 BH-11 41.85 11.60 30.25 30 11.85

7 1139.76 663.47 BH-12 45.88 11.20 34.68 30 15.88

8 1160.74 779.11 BH-13 43.26 9.30 33.96 40 3.26

9 1086.2 178.18 BH-14 44.1 14.80 29.30 30 14.1

10 1100.03 399.95 BH-15 42.44 12.20 30.24 30 12.44

11 1079.74 779.11 BH-16 44.26 8.70 35.56 40 4.26

12 1045.22 126.05 BH-17 44.62 12.10 32.52 30 14.62

13 1057.4 534.82 BH-18 43.1 9.45 33.65 30 13.1

14 1057.4 661.65 BH-19 45.83 9.00 36.83 30 15.83

15 1021.07 538.32 BH-20 43.57 9.20 34.37 30 13.57

16 964.28 178.18 BH-21 43.7 15.40 28.30 30 13.7

17 927.07 398.76 BH-22 42.15 12.10 30.05 30 12.15

18 902.48 461.67 BH-23 44.28 11.80 32.48 21 23.28

19 920.71 540.02 BH-24 44.34 10.95 33.39 40 4.34

20 936.36 642.7 BH-25 46.91 11.30 35.61 30 16.91

21 935.67 779.11 BH-26 44.78 8.50 36.28 40 4.78

22 1445.97 57.4 FPT-1 42.12 - - - -

23 1394.85 79.91 FPT-2 41.81 - - - -

24 1362.47 117.04 FPT-3 41.54 - - - -

25 1141.85 189.98 FPT-4 43.9 - - - -

26 1050.81 169.51 FPT-5 44.22 - - - -


57/359

* 55*


4.9.1 General :

The borehole No. BH-6,7,8,9,10,15,17 are found to contain blackish gravelly sand upto

5.0m depth. After 5m to 30m this location contains grayish black coloured highly weathered &

fractured basalt has water table is 11m to 12m depth below GL.

Whereas, in BH-11, 12, 13, 14, 16, 18, 19, 20, 21, 22, 23, 24, 25 & 26 are found to contain

variegated compact clay throughout the explored depth. Water table is about 12m depth below GL.

Whereas, at BH-13, 12m to 28m depth, purple coloured highly compact clay.


Laboratory tests conducted on soil samples collected from boreholes are discussed as below :

Layer I :

This layer is in medium dense to very dense sand and stiff to hard consistency with

variation in N value as 10 to refusal. The reddish soil at top shows very high swelling potential. The

atterbergs limits & other laboratory tests along with its variation is shown below :

Properties :

Moisture Content (%) :

Dry Density (g/Cc) :

Grain size analysis

Gravel (%) : 2 36

Sand (%) : 44 81

Silt & Clay (%) : 12 42

Clay (%) : Atterbergs limits



Shrinkage Limit :

Shear Properties

Cohesion (kg/cm2) :

Angle of friction (degree) :


Compression Index Cc : Co-eff. of vol. change mv : --

Co-eff. of consolidation Cv : --

Swelling Properties



Type of Soil : SM/SC/GM


58/359

* 56*


Properties :



Grain size analysisGravel (%) : 0.0

Sand (%) : 3 32

Silt & Clay (%) : 66 98

Clay (%) : 22 38

Atterbergs limits


Plasticity Index : 25 80

Shrinkage Limit : 8 10

Shear Properties







cm2/sec.

Swelling Properties


Swelling Pressure (kg/cm2) : 0.8 1.63

Type of Soil : CH / CI

Layer II :

This layer is found to contain as grayish black coloured, completely weathered to highly

weathered fractured hard rock basalt having core recovery varying from nil to 77% and Rock

quality designation as nil to 41%.


59/359

* 57*



Total five Field permeability test viz. FPT 4 and 5 were done in this zone. The analysis is

given as under :

FPT No. `Depth (m.) K value (cm/sec)

FPT-4 - Cancelled / not conducted

FPT-5 5.0 1.43 x 10-4

K-value varying from 10-4

cm/sec shows hard strata with medium permeability.


Borehole No. Type & Size ofFooting(m x m)


(m)


Based on Shear(t/m

2)

Net safe bearingcapacity basedon Settlement

(t/m2)

RecommendedNet safe bearing

capacity(t/m

2)


2.0

3.0

22

30

17

22

17

19


2.0

3.0

23

32

19

21

19

24

BH-15,6,9,23


2.0

3.0

26

34

16

20

16

20


2.0

3.0

11

14

48

54

11

14


2.0

3.0

11

14

44

50

11

14

BH-7, 8, 10, 11, 12,13, 14, 16, 17, 18,19, 20, 21, 22, 24,25, 26


2.0

3.0

11

14

39

48

11

14


60/359


61/359

* 59*




Layer I :

This layer is in medium dense to very dense consistency with variation in N value as 20 to

refusal. The reddish soil at this location does not show swelling potential. The atterbergs limits &

other laboratory tests along with its variation is shown below :

Properties :



Grain size analysisGravel (%) : 0 46

Sand (%) : 26 68

Silt & Clay (%) : 17 44

Clay (%) :

Atterbergs limits

Liquid Limit : 39 %

Plasticity Index : 17%

Shrinkage Limit :

Shear Properties


Angle of friction (degree) : 29.5 32


Compression Index Cc :

Co-eff. of vol. change mv : --

Co-eff. of consolidation Cv : --

Swelling Properties



Type of Soil : SM/SC/GM

Layer II :

This layer is found to contain grayish black coloured hard rock basalt having CR varying

from 27 to 97% and rock quality designation as nil to 95%.


62/359

* 60*



Total three Field permeability test viz. FPT 1,2 & 3 were done in this zone. The analysis

is given as under :

LocationFPT No.

Northing (m.) Easting (m.)

`Depth(m.)

K value (cm/sec)

FPT-1 1445.97 57.4 5.50 3.49 x 10-5

FPT-2 1394.85 79.91 5.50 1.3 x 10-4

FPT-3 1362.47 117.04 6.00 1.04 x 10-4

Co-eff. of permeability K varies from 10-5

to 10-4

cm/sec indicating very hard type of strata with

medium to low permeability.




(m)


Based on Shear(t/m

2)


Settlement(t/m

2)


capacity(t/m

2)


1.5

2.0

3.0

18

22

30

23

28

64

18

22

30


1.5

2.0

3.0

19

24

32

21

27

33

19

24

32


1.5

2.0

3.0

21

26

35

19

25

30

19

25

30


63/359

* 61*


[ 5 ] RECOMMENDATIONS :

5.1.1 General :

Based on location of structures design subsurface profile are prepared for the borehole

and are furnished in Appendix I & II. The bearing capacity recommendations area made for

shallow foundation for this unit.

5.1.2 Shallow Foundation :

The soil profile re

Documents

BECL_Soil Investigation Report