technical specifications for soil investigation

7/28/2019 Technical Specifications for Soil Investigation

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TECHNICAL SPECIFICATIONS

SUB SOIL INVESTIGATION



STANDARD SPECIFICATIONSOIL INVESTIGATION

TABLE OF CONTENTS

1.0 PURPOSE

2.0 SCOPE

3.0 TECHNICAL REQUIREMENTS

3.1 GENERAL

3.1.1 Location plan for soil exploration3.1.2 General Requirements from Contractor3.1.3 Mobilisation

3.2 BORING

3.2.1 Shell and Auger Boring3.2.2 Rotary Mud Circulation Drilling3.2.3 Drilling in Rock3.2.4 Borehole Depth3.2.5 Backfilling of boreholes3.2.6 Termination Criteria

3.3 IN-SITU SAMPLING

3.3.1 Trial Pits3.3.2 Undistributed Soil samples from Boreholes

3.3.3 Core samples of rock3.3.4 Water Samples

3.4 IN SITU TESTING

3.4.1 Standard Penetration Test3.4.2 Static Cone Penetration Test3.4.3 Vane Shear Tests3.4.4 Electrical Resistivity Test

3.5 LABORATORY TESTS

3.5.1 Atterberg Limits3.5.2 Natural Moisture Contents3.5.3 Dry Bulk Density and Void Ratio3.5.4 Specific Gravity3.5.5 Grain Size Distribution3.5.6 Triaxial Tests3.5.7 Unconfined Compression Test




3.5.8 Free Swelling Index3.5.9 Swelling Pressure Test3.5.10 Consolidation Tests3.5.11 Chemical Tests (Ph, sulphates, chlorides)3.5.12 Chemical Tests (Suitability for construction)3.5.13 CBR Tests for sub-grade soils (3 point tests)3.5.14 Proctor Density Tests3.5.15 Levels & Co-Ordinates of Test Location

3.6 REPORT




1.0 PURPOSE

The purpose of this standard is to define specifications to be followed for SoilInvestigation work at Paradeep project site, Orissa.

2.0 SCOPE

These specifications cover the procedure for soil investigations for foundations.The work shall be carried out in accordance with the specification set out belowand as directed by the Engineer-in-charge, wherever necessary. TheseSpecifications conform to the relevant Indian Standards on Soils and Foundationsfor field investigations and Laboratory testing. Reference to any code in thesespecifications shall mean the latest revision of the code unless otherwisementioned. In the event of any conflict between the requirements in thesespecifications and the referred codes, the former shall govern.

3.0 TECHNICAL REQUIREMENTS

3.1 GENERAL

The purpose of the proposed sub-soil investigation programme is to provideadequate information on sub-surface and surface conditions for the foundationsand other sub-structures for the proposed project, leading to their economical andsafe designs.

The planning of the work, choice of the method of boring, selection of the type of

samples and procedure for sampling though indicated in the Tender. Tenderer,however, shall furnish his tentative programme regarding the above along withhis offer which, necessarily, should take into account the site conditions and timeschedule for completing the work, comprising subsurface features, borings, in-situtests, sampling, visual observations and laboratory tests of samples, reporting ofthe test results, including discussions, correlating the field and the laboratory testvalues and recommendations.

These specifications cover the work pertaining to subsoil investigations andrecommendations for economical and safe design of foundations and sub-structures for the proposed project site.

3.1.1 Location plan for soil exploration

A location plan drawing showing various facilities with proposed facilities beingmarked as Red are attached.The exploration programme in the site will befinalized by the successful bidder in consultation with Project-in-charge as suitedto the site conditions.




3.1.2 General Requirements from Contractor

The CONTRACTOR shall have on site all required survey instruments to carryout the work accurately according to specifications and drawings. All thespecified locations for boreholes and field tests shall be set out at site by theCONTRACTOR from two established reference grid lines which will be shown tohim by the ENGINEER IN-CHARGE. If required, the CONTRACTOR shall setout the base lines and the locations of boreholes and field tests with reference tothe property line as indicated by the ENGINEER IN-CHARGE. At each location ofboreholes, plate load tests and other field tests, the CONTRACTOR shallestablish the ground level prior to commencing of the operations. The groundlevel shall be related to an established benchmark or to a GTS benchmark or asdirected by the ENGINEER IN-CHARGE.If the area, where the field tests are located, is likely to be inundated by tidalwaters, the field work shall include provision for temporary fill, erection andremoval of platforms, making good the ground, access, etc., as necessary forcarrying out the work in this area. Payment, if any, for any such works will be asper rate quoted in the Bill of Quantities. It is expected that the cost of the samehas been catered for in rates for relevant items and no extra claims will beentertained on this account.

The Contractor shall submit with his bid the list of equipment / apparatus hewould mobilise at site, if work is awarded to him. To complete the work within thestipulated time, the Contractor shall, if necessary, mobilise additional equipmentwithout additional cost to the Owner.

3.1.3 Mobilisation

The Contractor shall mobilise adequate plants and equipments, instruments andpersonnel (skilled and unskilled) required to carry out the soil investigation work,including access, filling, provision of platforms, etc.

This scope also includes demobilisation of all equipments / personnel in orderlymanner so as to keep the site clean for any further work by Owner. This shouldbe to the satisfaction of Owners and Consultant's Representative. Charges forthese items of work are paid as lumpsum; no extra payment will be made forsubsequent mobilisation of any accessories and equipments.

Based on the field examination or tests, borelogs shall be prepared in accordancewith IS:1498. On completion of the field records, the soil investigator shalldiscuss and decide in consultation with the consultants, the schedule of tests tobe performed and the exact number of samples to be tested for each test.

Mode of Payment: The payment for this item will be made after inspection andapproval of equipment, instruments, etc. mobilised to the site by EIC. The EIC




will certify the item for payment only after satisfying that the equipments are inworking condition.

3.2 BORING

Boring shall be carried out in accordance with the provisions of IS:1892 and asper the specifications given below:

3.2.1 Shell and Auger Boring

Augers shall be of helical or post hole type and may be manually operated. Thediameter of the borehole shall be 150mm or as specified in BOQ.

Uncased holes shall be permitted only upto a depth where the sides of the holecan stand unsupported. In case side fall is noticed, steps shall be takenimmediately to stabilise the holes by using bentonite slurry or by casing pipes asdirected by the Engineer-in-Charge.

No water shall be added while boring through cohesive soils and cohesionlesssoils above water table. While boring through cohesionless soil below watertable, water in the casing shall always be maintained at or above the water table.

The cuttings brought up by the auger shall be carefully examined and soildescriptions duly recorded. Representative samples shall be preserved forlaboratory testing.

Wherever in-situ tests are conducted and undisturbed samples are obtained atspecified depths from the borehole, care shall be taken to ensure that theborehole is properly cleaned and free from foreign matters at the time ofconducting these operations.Water table in the boreholes shall be carefully recorded and reported. One of thefollowing methods shall be adopted for measuring the water table:

a) The water table in the borehole shall be allowed to stabilise after depressing thewater level adequately by bailing. Stabilising of the borehole sides and bottomshall be ensured at all times.

b) The borehole shall be filled with water and then bailed out to various depths.Observations shall be made at each depth to see if the water is rising or falling.The depth at which neither a fall nor a rise is observed shall be considered as thewater table depth. This shall be established by three successive readings ofwater levels taken at intervals of 2 hours.

c) Hyorslev’s Method




The water level shall be depressed by bailing (to say D below groundlevel) and shall then be allowed to rise. Water rise at suitable equalintervals of time shall be recorded. The distance of depressed water levelfrom the actual water table shall be obtained by the following formula:

H1²Ho = ______

H1 – H2

Where,

Ho = distance of depressed water level from actual watertable,

H1 & H2 = two successive rises of water level in the borehole forthe same time interval

The water table depth (Hd) from ground level shall be determined as under:

Hd = D – Ho

Three sets of observation shall be made and the average value of Hddetermined.

Method (a) is suitable for permeable soil while methods (b) and (c) aresuitable for both permeable and impermeable soils. The Engineer-in-Charge shall indicate the method to be followed.

Immediately on completion of a borehole, bore log shall be prepared in anapproved Performa and submitted to the Engineer-in-Charge in duplicate.

Auger shall be used for soft to firm clay and for silty deposits at upper depths of10 metres or upto the water table, whichever is deeper. For deeper depths insuch deposits and for very stiff to hard clays and dense sands located at anydepth, use of shell may be made.

While boring in soft clays and in sandy deposits below water table, it shall be

ensured that the shell diameter shall be at least 25 to 50 mm less than the casingdiameter. This is to ensure that suction is not created in the borehole duringwithdrawal of the shell with consequent “Caving-in and blowing” in the boreholes.

3.2.2 Rotary Mud Circulation Drilling

The drilling shall be carried out (as per IS:1892) by use of a suitable mechanicalrig.




Drilling upto water table shall be done by auger and provisions of clauses 4.1.2.1to 4.1.2.8 shall apply. Below the water table drilling by rotary mud circulation shallbe adopted.

Use of percussion tools may be permitted in very stiff to hard clays and densesandy deposits only after obtaining written permission from Clients / Consultants.

3.2.3 Drilling in Rock

In rock strata, boring shall be done by using a rotary cutting tool tipped withdiamonds and equipped to recover cores.

Drillhole size shall generally be NX. However, in some cases other size holesmay be specified

Core barrels shall be double-tube ball-bearing, swivel type, with the core lifterlocated in the lower end of the inner barrel. The Bidder shall confirm the samewith his bid.

Drilling shall be carried out in such a manner that maximum core is recovered.This requires close surveillance of wash water, drilling pressures, lengths of runs,etc. The drill bit shall be withdrawn and the core removed as often as may benecessary to secure the maximum possible amount of core. CONTRACTORshall ensure that drilling is carried out with necessary skill and expertise.

3.2.4 Borehole Depth

All boreholes shall be sunk to depths as specified in tender document.

It may be difficult to continue the boring due to presence of gravels and boulders.In this case, boreholes, shall be advanced upto 6.5 to 7.0 m depth by cementgrouting using Ax size drill, followed by drilling with 3½" casing Hx size drill or of alarger size.

Initially about 1 - 1.5m depth shall be used, using Ax size drill, followed by 1:1cement water grouting.

After about 12 -24 hours of grouting, the boreholes shall be redrilled with casingitself (which may have a bit at the bottom or simple teeth). Further drilling shallthen be carried out upto another 1 - 1.5 m followed by grouting and redrilling.

This sequence will be continued till 6.5 - 7.0 m depth with SPT @ every 1 minterval.




3.2.5 Backfilling of boreholes

On completion of boreholes, backfilling shall be carried out with an approvedmaterial as and when directed by the Engineer-in-Charge. Unless otherwisespecified, the excavated soil shall be used for the purpose.

3.2.6 Termination Criteria

If very hard strata is met within the borehole at depths shallower than specified intender documents, the borehole shall be advanced by coring using double tubecore barrel. The borehole may be terminated 3m below the depth where N > 75values are obtained consistently.

3.3 IN-SITU SAMPLING

3.3.1 Trial Pits

Trial pits shall be of minimum 3m x 3m size at base so as to permit easy accessfor a visual examination of the walls of the pit and to facilitate sampling and in-situtesting operations.

Precautions shall be taken to ensure the stability of pit walls, if necessary by theprovision of shoring. Arrangements shall be made for dewatering, if the pit isextended below water table.

In-situ tests shall be conducted and undisturbed samples obtained immediatelyon reaching the specified depths, so as to avoid substantial moisture changes inthe subsoil.

After completion of tests and examination, the pits shall be suitably backfilled asdirected by the Engineer-in-Charge. Unless otherwise specified, the excavatedsoil shall be used for this purpose.

3.3.2 Undistributed Soil samples from Boreholes

Samples for recovering undistributed samples from cohesive soils at the specifieddepth shall conform to IS:2132. However, use of samples less than 70mm

diameter shall not be permitted.

The sampling procedures shall conform to IS:2132. Both the area ratio of thecutting edge, as well as recovery ratio of the sample shall be measured andreported. For normal soils, area ratio of the sampling tubes, shall conform toIS:2131, that is, it may vary from 10.9% to 12.4% but for sampling in very hardand dense soils, use of thick walled sampling tubes with area ratio not exceeding20% may be permitted subject to the approval of the Engineer-in-Charge.




In order to reduce the wall friction, suitable precaution such as oiling the insideand outside of the sampling tubes shall be taken. The sampling tube shall havesmooth finish.

In soft to firm clays, undisturbed samples shall be collected by pushing the tubecontinuously without impact or twisting. Driving of sampling tubes shall bepermitted only if stiff to very stiff and hard deposits exists.

For highly sensitive soils, piston samplers shall be employed.

For soft clays exceeding more than 15M depth from the ground level, collection ofundisturbed samples shall be supplemented by the In-Situ Vane Shear Tests.

The top and bottom of the sample shall be clearly marked on the sampling tube.Undisturbed samples shall be tested within a period of two weeks of taking

them from the boreholes or trial pit.

If any space is left between the end of the tube and top of wax, the same shall betightly packed with saw dust or any other suitable material. A close fitting lid orscrewed cap shall then be placed on each end of the tube and held in position byadhesive tape.

3.3.3 Core samples of rock

The ease or difficulty of drilling at different depths shall be carefully noted andrecorded during drilling. The returning drill water shall be kept constantly underobservation and its character, such as, its clarity or its turbidity; its colour etc.shall be recorded.

Coring runs shall be limited to a maximum length of 2.0m. When less than 50%of the core is recovered from a run or when a geological features is to beaccurately determined, the length of the run shall be reduced to 1.0m unlessdirected otherwise by the ENGINEER.

The core shall be removed from the drillhole immediately if blocking of the bit orgrinding of the core is apparent, regardless of the length of run, which has been

made.The CONTRACTOR shall not use drilling mud or any lubricant in the drillholeother than water.

For each run, Core Recovery and Rock Quality Designation (RQD) shall be notedcarefully, immediately after cores are taken out of the barrel.




Each and every core piece shall be serially and sequentially numbered from topdownwards as soon as the core pieces are removed from the core barrel. Theserial number shall be painted with good quality enamel paint.

All core pieces shall be placed in core boxes in serial order in correct sequencefrom top downwards. Core boxes shall be made according to specifications laiddown in IS:4078.

The cores, arranged in core boxes noted earlier, shall be submitted to theOWNER / ENGINEER on submission of the report. The cost of this including thecost of core boxes will be presumed to be included in the drilling rate.

If core recovery is less than 20%, the payment for drilling shall be same as thatfor boring in soil at appropriate depths.

3.3.4 Water Samples

Water samples shall be collected from boreholes as specified. Water samplesshall be collected before the addition of water to the hole unless that is notpossible. If this is not possible, then prior to collection of water sample, waterlevel in the bore hole shall be lowered upto the bottom of the borehole thenallowed to rise by water seeping through the walls of the borehole. The watersample shall then be collected. Care shall be taken to see that water sample isnot contaminated by surface water or rainwater.

In some cases water samples may be required to be collected from differentdepths, if so specified. In such cases it is advisable to collect the samples on thecompletion of the relevant borehole unless a suitable sampler to collect watersample from different depths below free water surface is used. To collect thewater sample, in absence of a suitable sampler the borehole shall be dewatered.The sample shall then be collected when the water rises to the required depth. Ifspecified, ground water sample shall also be collected from trial pits. If there areany wells within the area investigated, one water sample from each well shall alsobe collected. If specified, water samples shall also be collected from well (s)located nearby the area being investigated. The water sample shall becollected in an air tight, scrupulously clean glass or inert plastic bottle or jerry can.The bottle / can shall be rinsed three times with water being sampled, before

filling. The quantity of each water sample collected shall be about 1 litre.

Water samples shall be tested as soon as possible after sampling for sulphate(as SO3) and chloride contents and its pH, and for other tests as specified.




3.4 IN SITU TESTING

3.4.1 Standard Penetration Test

The test shall be conducted at specified intervals or at a depth where the stratachanges, whichever occurs earlier.The test shall be carried out by driving a standard split spoon by means of 65 kghammer with a 75 cm free fall. Detailed procedure of testing, as specified inIS:2131. 'Method of Standard Penetration Tests in Soils' shall be followed. Thesamples obtained in the split spoon shall be labelled and preserved foridentification tests in the laboratory.

Standard penetration test shall be conducted at 1.5m interval. Sequence ofconducting SPT shall be changed in each bore hole. Say for first bore hole SPTstarted at 1.5 m depth then 3.0 m,……….. etc. For next bore hole it shall bestarted at 1m depth then 2.5m …… etc. Similiarly for other bore hole. So thatstaggered value of SPT’s obtained for entire site.

Disturbed samples to be collected (including packing and transporting) and sentto the Laboratory as per specifications. The standard penetration test shall bediscontinued when N is greater than 75 blows for 30 cms of penetration.

3.4.2 Static Cone Penetration Test

The equipment used for this test shall conform to the requirements of IS:4968(Part III).

The capacity of the equipment to be used for test shall not be less than 10.0 tons.

The test shall not be carried out on gravelly soils or for soils with standardpenetration value 'N' greater than 50.

Test Procedures

Test procedure shall meet the requirements of IS:4968 (Part III). Some of theimportant points of the procedure are given below :

a) The cone is pushed through a distance in accordance with the design ofthe equipment and the need for the sub-strata and the cone resistancenoted. The cone and the friction jacket are pushed together subsequentlyfor a distance depending upon the design of the cone and frictionresistance noted. This procedure is repeated at predetermined intervals.

b) Equipment shall be securely anchored to the platform at the test point forobtaining the required reaction.




c) The rod of the driving mechanism shall be brought to the top most position.The cone friction jacket assembly shall be connected to the first soundingrod and the mantle tube. The assembly shall be positioned over the testpoint through the mantle tube guide and held vertically. The plunger of thedriving mechanism shall be brought down so as to rest against theprotruding sounding rod.

d) To obtain the cone resistance, only the sounding rod shall be pushed.Switching the gear clutch to the slow position, the drive handle shall beoperated at a steady rate of 1 cm / sec. approximately, so as to advancethe cone only, to a depth which is possible with the cone assemblyavailable. During the pushing, the mean value of resistance as indicatedby pressure gauges shall be noted ignoring erratic changes.

e) For finding combined cone and friction resistance of the soil, the soundingrod shall be pushed to the extent the cone has been pushed, at the rate of1 cm / sec. noting mean resistance on the gauges.

f) The above procedure shall be repeated after pushing the combined conefriction jacket and mantle tube assembly to the next depth at which the testis to be performed.

g) The sequence of operation of the equipment shall be as per Fig. 5 ofIS4968 (Part 3).

The proforma for record of results of static cone penetration test shall be asapproved by Consultants.

3.4.3 Vane Shear Tests

These tests shall be conducted in soft to firm clays and sensitive clays. Thesetests shall also be conducted in case of stiff fissured clays where samples cannotbe taken.

Tests shall be generally conducted through boreholes.

The apparatus used for vane shear tests shall satisfy the requirements as perIS:4434.

For test from bottom of Borehole:

a) Vane shall consist of four mutually perpendicular blades, as illustrated inIS:4434. The height of the vane should be twice the blade diameter. It isrecommended that the diameter of the vane should be 37.5, 50, 75 or 100




mm. The design of the vane shall be such that it causes as littleremoulding or disturbance as possible to the soil when inserted into theground for a test. The blades shall be as thin as possible, consistent withthe strength requirements. The vane should not deform under themaximum torque for which it is designed. The rotating trating edge of thevane blades shall be sharpened having an included angle of 90 deg. Thevane blades shall be welded together suitably either directly or to a centralrod, the maximum diameter of which should preferably not exceed 12.5mm.

The area ratio of the vane shall be kept as low as possible and shall notexceed 18% for the 37.5 mm vane and 12% for the 50, 65, 70 and 100 mmdiameter vanes. The area ratio may be calculated using the followingformula:

Ar = 8t (D-d) + ∏ d²

---------------------- x 100 (%) ∏ d²

WhereAr = area ratio in percentt = thickness of vane blades in mm.D = overall diameter of vane in mm and,d = diameter of central vane rod including any enlargement due

to welding in mm.

Note 1 : The vane selected should be the largest size suitable for thegeneral soil conditions at a site.

The vane rod (the rod to which the vane blades are fixed) may beenclosed in a suitably designed sleeve from just above the blades andthroughout the length it penetrates the soil to exclude the soil particles andthe effects of soil adhesion. This sleeve shall commence above the bladesat a distance equivalent to about two diameters of the vane rod.

Note 2 : The vane shall be frequently checked for straightness.

b) Torque Applicator

The torque applicator shall have a clamping device to rigidly secure it tothe anchor casing and shall have an attachment to securely hold the stringof rods connecting the vane.

The instrument shall be capable of applying a torque to the vane throughthe string of rods and to measure the same. It should also have a device




to read the angular rotation of the upper end of the extension rods. Thetorque applicator shall be provided with speed control so that the rate ofrotation may be maintained at 0.1 deg. / sec. Friction exerted by the torqueapplicator shall be of negligible magnitude and shall be checkedperiodically. Depending upon the estimated shear strength of the soil thefollowing table (Table 1) may be used as a guide for the selection of torqueapplicator of capacity 60 N.m (600 Kgf.cm) .

TABLE - 1

SELECTION OF TORQUE APPLICATOR

Estimated Shear Strength in KN / Sq.m (Kgf / sq.cm)

Vane size (dia.) suitable for use with600 Kgf. cm torque applicator

10 (0.1)20 (0.2)30 (0.3)40 (0.4)50 (0.5)60 (0.6)70 (0.7)

All sizesAll sizes except 100 mm sizeAll sizes except 100 mm sizeAll sizes except 75 mm size & 100mm sizeAll sizes except 75 mm size & 100mm size37.5 mm and 50 mm size37.5 mm and 50 mm size

The capacity and accuracy of the instrument shall be one of the following

as may be specified by the purchaser:

a) Measure torque upto 60 N.m (600 kgf.cm) to an accuracy of 1 N.m (10kgf.cm), or

b) Measure torque upto 200 N.m (2000 kgf.cm) to an accuracy of 2.5 N.m(25 kgf.cm)

c) Rod System: The string of torque rods connecting the vane to thetorque applicator, called the rod system may be of quick coupling typeor of the threaded type. The length of the rods shall be preferably be1m with a few of smaller lengths. These rods shall have sufficientdiameter such that their elastic limit is not exceeded when the vane isstressed to its capacity (see Note 3). The threaded rods shall be socoupled that the shoulders of the male and female ends shall meet toprevent any possibility of the coupling tightening when the torque isapplied during the test. If a vane housing is used, the torque rods shallbe equipped with well-lubricated bearings where they pass through thehousing. These bearings shall be provided with seals to prevent soilfrom entering them. The torque rods shall be guided so as to prevent




friction from developing between the torque rods and the walls ofcasing or boring.

Note 3 : If torque versus rotation curves to be determined, it is essential thatthe torque rods be calibrated (prior to the use in the field). The amount ofrod twist (if any) shall be established in degree per metre per unit torque.

This correction becomes progressively more important as depth of testincreases. The calibration shall be made at least to the maximum depth oftesting anticipated.

d) Dummy Rod

Of dimensions equal to that of the vane rod of the vanes used.

e) Guides for Rod

Of suitable type provided with ball bearing attachment so as to enable therod to rotate freely (see Note 4).

Note 4 : During the test, it is essential that the rods and vane are placedcentrally in the borehole. For this purpose guides shall be used at aninterval in depth of not more than 5m.

f) Drilling Equipment

The equipment shall provide a clean hole of the required diameter forinsertion of the vane to ensure that the vane test is performed onundisturbed soil.

g) Jacking Arrangement

For pushing the shoe and vane (where required).

h) The apparatus shall be checked and calibrated as and when required.

For Tests by Direct Penetration from Ground Surface

a) Vane

As specified in 3.4.5 a) In addition the vane shall be suitably protected bya shoe.

b) Rod System




As specified in 3.4.5 c) and of suitable type.

c) Extension Pipes

About one metre length with coupling on the outer face to case the hole.

d) Torque Applicator

As specified in 3.4.5 b)e) The apparatus shall be checked and calibrated as and when requested.

Procedure for tests from the bottom of a borehole

Sink the bore upto the depth required and extend the casing upto the full depth.If the casing is loose, secure it so that it does not move during the tests. Fix thetorque applicator anchor plate to the casing.

Connect the vane of suitable size (see Note 1) to the rods and lower it to thebottom of the bore-hole, put guides at suitable intervals but not more than about5m as the rods are extended. Push the vane with a moderately steady force uptoa depth of 5 times the diameter of the borehole below the bottom of the boreholeor shoe. Take precaution to make sure that no torque is applied to the torquerods during the thrust. No hammering shall be permitted. Fix the torqueapplicator with frame to the anchor plate and connect the rods to it. Tighten thetorque applicator to the frame properly.

Allow a minimum period of 5 minutes after insertion of the vane. Turn the gearhandle so that the vane is rotated at the rate of 0.1 deg / s.

Note the maximum torque reading attained. If necessary, note the torqueindicator dial gauge readings at half minute intervals and continue rotating thevane until the reading drops appreciably from the maximum.

Just after the determination of the maximum torque, rotate the vane rapidlythrough a minimum of ten revolutions. The remoulded strength should then bedetermined (see C; above within one minute after completion of the revolutions).

Remove the vane testing assembly, continue boring and collect soil sample fromthe level of the vane testing for laboratory analysis to ascertain whether thedeposit will behave as a purely cohesive soil.

In cases where a sleeve is not provided for the vane rod and the soil is in contactwith the rod, determine the friction between the soil and the vane rod byconducting tests at appropriate depths using the dummy rod corresponding tothat of the vane used in the test. The test should be conducted as with the vane




except that the vane is replaced by dummy rod. The test should be conducted inan adjacent borehole at the same depth at which the vane tests were conducted.The dummy rod should be pushed into the ground to the same distance as thevane rod at that depth.

Following points shall, however, be carefully supervised in the field:

a) Straightness of vane shall be checked while the entire assembly of vaneconnected with rod is lowered to the bottom of boreholes. Vane shall bepushed with a moderate steady force upto a depth of five times the borehole diameter below the bottom of boreholes. Precautions shall be takento ensure that no torque is applied to the torque rods during the thrust. Nohammering shall be done.

b) An interval of 5 minutes shall be allowed to lapse after insertion of vane.

c) Torque indicator readings shall be noted at intervals of 30 seconds untilthe vane readings drop appreciably from the maximum.

d) Samples shall be collected from the levels at which the tests have beenconducted.

Tests by Direct Penetration from Ground Surface

Rods shall remain tight when vane is lowered. Guides shall be placed at every3m to centralise and reduce friction between rods and extension pipe.

Records

Records of vane test shall be maintained in approved proforma.

3.4.4 Electrical Resistivity Test

This test shall be conducted as per Appendix B, Clause 3.2 of IS1892 - 1979.The test shall be done by using 4 points. The locations where ERT to beperformed shall be finalized in consulatation with EIC..

3.5 LABORATORY TESTS

The following laboratory tests shall be conducted on samples collected from thefield covering all the bores using procedures specified in the relevant IndianStandards. All the Laboratory Tests shall be conducted by skilled personnel only.

3.5.1 Attenberg Limits




The tests result should include liquid limit and plastic limit of the soil samplestested. These tests should be conducted as per IS:2720 Part V.

3.5.2 Natural Moisture Content

In case of organic soils, the oven temperature shall be 60 deg. C and not 105deg.C.

3.5.3 Dry Bulk Density and Void Ratio

3.5.4 Specific Gravity

This test should be conducted as per IS:2720, Part 3.

3.5.5 Grain Size Distribution

Wherever applicable both the sieve and hydrometer analysis shall be conductedto indicate complete range of grain size in the soil sample tested. Generally,Hydrometer analysis will be carried out, wherever percentage passing No.200sieve is greater than 30%.

3.5.6 Triaxial Tests

These tests shall be done on specimens saturated by the application of backpressure. Only if the water table is at sufficient depth so that chances of its risingto the base of the footing are meager or nil, shall the triaxial tests be performedon specimens at Natural Moisture Content. The magnitude of the back uppressure applied shall be indicated in the report.

All stress diagrams as well as Mohr-circle envelopes shall be included in thereport.E-value shall be determined from the triaxial tests. Relevant corrections appliedto the computer 'E' shall be clearly illustrated in the report.

3.5.7 Unconfined Compression Test

This test shall be conducted as per IS:2720, Part X.

3.5.8 Free Swelling Index

This test shall be conducted as per IS:2911, Part III.

3.5.9 Swelling Pressure Test




This test shall be conducted as per Draft Standard circulated by TechnicalCommittee on Expansive Soils (TC-6) of International Society of Soil Mechanicsand Foundation Engineering; 'Evaluation of Swelling Pressure of Expansive Soilin Laboratory' (circulated in November, 1990).

3.5.10 Consolidation Tests

The following loading stage shall be employed : 0, 0.1, 0.25, 1.0, 2.0, 4.0 and 8.0kg / sq.cm. From e Vs log p curves, preconsolidation pressure shall bedetermined to establish whether the soil is normally consolidated or overconsolidated. The point (e, p) showing initial condition of the soil under test mustbe specifically marked on the consolidation curves. Settlement predictions basedon the field virgin compression curve shall only be acceptable. The procedureadopted in respect of obtaining compression indices from the field curve and thatfor computing settlements for the type of clay under consideration shall be clearlyillustrated in the report.

It is to be noted that deviations from the standard procedure of performingconsolidation tests given in IS:2720 are permissible in order to enablecomputation of settlements based on the above procedure i.e. cycles (s) ofloading, unloading and reloading shall be employed wherever required.

The following curves shall be included in the report :

a) e vs : log p

b) e vs : p

c) Compression vs : log t or compression vs t.

The choice of relationship depends upon the shape of the plot, which enables aclear determination of Cv, the coefficient of consolidation.

The time period required for 50% and 90% primary consolidation should be givenin the report.

Computation of secondary settlements, if significant, shall also be made andincluded in the report.

3.5.11 Chemical Tests On Water & Soil

Chemical tests shall be conducted on soil and water samples to report thefollowing:




a) pHb) Chloridec) Sulphated) Sulphitee) Organic contentsf) Total hardness

3.5.12 Chemical Tests (Suitability of water for Construction)

These tests shall be carried out to check suitability of water for constructionpurpose as required by IS:456. Other Inorganic Tests as required by WorldHealth Organisation (WHO) to test suitability for drinking purpose shall also becarried out.

3.5.13 CBR Tests for Sub-Grade soils (3 Point Tests)

These tests shall be conducted on soaked and unsoaked samples generally asper IS: 2720 Part XVI. Bulk samples for laboratory tests shall be selectedrandomly from various road locations and also from locations of stacking areas inconsultation with Engineer-in-Charge. The 3 point test shall consist ofpreparation of samples with 15, 25, 35 blows per layer, which will give threedifferent densities to soil and then testing each for soaked condition.

3.5.14 Proctor Density Tests

These tests shall be conducted as per IS: 2720 Part VII samples collected

randomly in consultation with Engineer-in-Charge.

3.5.15 Levels & Co-Ordinates of Test Location

Contractor shall establish and tabulate reduced levels and co-ordinates of varioustest locations. Any expense on this account shall be deemed to have beenincluded in the quoted rates.

3.6 REPORT

Two copies of Draft\Interim Report shall be submitted to Client / Consultant

before preparing Final Report.

The record shall be prepared with due regards to above given

requirements in a draft format and submitted for review and comment as soon as

field and laboratory works are completed. Contractor shall incorporate the

comments/ remarks, if any, furnished by HPCL upon review of the Draft Report




and submit the final report. The draft copy of the report shall in general include

but not be limited to the following :

1. Plot plan showing all the test locations with respect to reference bench

mark.

2. General Geological information of the site

3. Character and genesis of soil

4. Procedure of investigation and methods of various testing adopted.

5. Detailed bore-logs indicating co-ordinates, reduced levels, ground water

table etc., sub soil profiles along various profiles along various sections

indicating borehole no. depth wise in-situ tests like SPT and other lab

results etc.

6. Generalised soil profile of the underlying strata in cross section and

longitudinal section wise, shall be furnished based on the bore log in grid

pattern

7. All field and laboratory test results shall be plotted against depth and also

in tabular form

8. Summary of results obtained from various tests and other interpretation to

evaluate various soil parameters.9. Recommend suitable foundation for Above ground Petroleum products

storage tanks. The diameter of the tanks will be advised during soil testing.

10. Recommend suitable depth of foundation and foundation to be adopted for

MCC Room/ Control Room Buildings, Pump House Sheds, Roads,

Railway siding and Loading Gantry Structure proposed at the above

location.

11. The Contractor shall recommend in the report the suitable foundation

system or ground improvements to be adopted for Enclosure wall, roads,

drains, Pipeline pedestals and other structures; the permissible bearing

pressure expected at the founding level with allowable settlement, if any;

details of soil improvements, if any and any other aspect which will have

any bearing on the proposed construction. The Contractor shall also




provide the suggested filling materials characteristics/ parameters

considering locally available soils and economics.

12. Ultimate and safe bearing capacity from shear as well as from settlement

criteria (i.e. for 25mm and 40mm) for the shallow, combined or raft

footings.

13. Recommendation for pile foundation (If necessary) including types of piles,

size and depth of pile and safe load in vertical, lateral and pull out.

14. Comments on chemical aggressiveness of soil and ground water on

reinforced concrete, steel and other building materials and firm

recommendations on remedial/ preventive measures.

15. Recommendation of CBR value for design of road, pavement etc.

16. Recommendation of soil resistivity to be considered for design purpose.

17. Recommendation of design parameters for pressure meter test.

Recommendation of foundation system with detailed calculations from

pressure meter test result.

18. Recommendation regarding ground water fluctuation, horizontal and

vertical permeability of sub soil strata.

Contractor shall submit 6 Sets of Final Reports along with soft copy in CD.

technical specifications for soil investigation

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