UNDP TERMS OF REFERENCE AND TECHNICAL SPECIFICATIONS FOR SUB SOIL INVESTIGATION FOR UNDP HOUSING AT UNOCA COMPOUND

Transcription

1 UNDP UNITED NATIONS DEVELOPMENT PROGREM TERMS OF REFERENCE AND TECHNICAL SPECIFICATIONS FOR SUB SOIL INVESTIGATION FOR UNDP HOUSING AT UNOCA COMPOUND Issued for Tender only Kabul - Afghanistan September, 2013

2 Index 1.0 PURPOSE 2.0 SCOPE 3.0 TECHNICAL REQUIREMENTS 3.1 GENERAL Location plan for soil exploration General Requirements from Contractor Mobilisation 3.2 BORING Shell and Auger Boring Rotary Mud Circulation Drilling Drilling in Rock Borehole Depth Backfilling of boreholes Termination Criteria 3.3 IN-SITU SAMPLING Trial Pits Undistributed Soil samples from Boreholes Core samples of rock Water Samples 3.4 IN SITU TESTING Standard Penetration Test Static Cone Penetration Test Vane Shear Tests Electrical Resistivity Test 3.5 LABORATORY TESTS Atterberg Limits Natural Moisture Contents Dry Bulk Density and Void Ratio Specific Gravity Grain Size Distribution Triaxial Tests Unconfined Compression Test Free Swelling Index Swelling Pressure Test Consolidation Tests Chemical Tests (ph, sulphates, chlorides) Chemical Tests (Suitability for construction) CBR Tests for sub-grade soils (3 point tests) Proctor Density Tests Levels & Co-Ordinates of Test Location 3.6 REPORT 2

3 1.0 PURPOSE The purpose of this standard is to define specifications to be followed for Soil Investigation work for the mentioned project. 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 below and as directed by the UNDP Engineer, wherever necessary. These Specifications conform to the relevant Standards on Soils and Foundations for field investigations and Laboratory testing. Reference to any code in these specifications shall mean the latest revision of the code unless otherwise mentioned. In the event of any conflict between the requirements in these specifications 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 provide adequate information on sub-surface and surface conditions for the foundations and other sub-structures for the proposed project, leading to their economical and safe 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 with his offer which, necessarily, should take into account the site conditions and time schedule for completing the work, comprising subsurface features, borings, in-situ tests, sampling, visual observations and laboratory tests of samples, reporting of the test results, including discussions, correlating the field and the laboratory test values and commendations. These specifications cover the work pertaining to subsoil investigations and recommendations for economical and safe design of foundations and substructures for the proposed project site Location plan for soil exploration A location plan drawing showing various facilities with proposed facilities being marked as Red are attached. The exploration programme in the site will be finalized by the successful bidder in consultation with UNDP Engineer as suited to the site conditions General Requirements from Contractor The CONTRACTOR shall have on site all required survey instruments to carry out the work accurately according to specifications and drawings. All the specified locations for boreholes and field tests shall be set out at site by the CONTRACTOR from two established reference grid lines which will be shown to him by the UNDP Engineer. If required, the CONTRACTOR shall set out the base lines and the locations of boreholes and field tests with reference to the property line as indicated by the UNDP Engineer. At each location of boreholes, plate load tests and other field tests, the CONTRACTOR shall establish the ground level prior to commencing of the operations. The ground level shall be related to an established benchmark or to a GTS benchmark or as directed by the UNDP Engineer. If the area, where the field tests are located, is likely to be inundated by tidal waters, the field work shall include provision for temporary fill, erection and removal of platforms, making good the ground, access, etc., as necessary for carrying out the work in this area. No extra payment for such cases in due, but whatever has covered in the Bill of Quantities under the Soil/Geo Investigation task s cost Mobilisation The Contractor shall mobilise adequate plants and equipment, instruments and personnel (skilled and unskilled) required to carry out the soil investigation work, including access, filling, provision of platforms, etc. 3

4 This scope also includes demobilisation of all equipment / personnel in orderly manner so as to keep the site clean for any further work by Owner. No extra payment for such activities in due, but whatever has been covered in the Bill of Quantities under the Soil/Geo Investigation task s cost. Based on the field examination or tests, bore logs shall be prepared in accordance with IS: On completion of the field records, the soil investigator shall discuss and decide in consultation with the consultants, the schedule of tests to be performed and the exact number of samples to be tested for each test. 3.2 BORING Boring shall be carried out in accordance with the provisions of IS: 1892 and as per the specifications given below: Shell and Auger Boring Augers shall be of helical or posthole type and may be manually operated. The diameter of the borehole shall be 150mm or as specified in BOQ. Uncased holes shall be permitted only up to a depth where the sides of the hole can stand unsupported. In case side fall is noticed, steps shall be taken immediately to stabilise the holes by using bentonite slurry or by casing pipes as directed by the UNDP Engineer. No water shall be added while boring through cohesive soils and cohesion-less soils above water table. While boring through cohesion-less soil below water table, 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 soil descriptions duly recorded. Representative samples shall be preserved for laboratory testing. Wherever in-situ tests are conducted and undisturbed samples are obtained at specified depths from the borehole, care shall be taken to ensure that the borehole is properly cleaned and free from foreign matters at the time of conducting these operations. Water table in the boreholes shall be carefully recorded and reported. One of the following methods shall be adopted for measuring the water table: a) The water table in the borehole shall be allowed to stabilise after depressing the water level adequately by bailing. Stabilising of the borehole sides and bottom shall 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 the water table depth. This shall be established by three successive readings of water levels taken at intervals of 2 hours. c) Hyorslev s Method The water level shall be depressed by bailing (to say D below ground level) and shall then be allowed to rise. Water rise at suitable equal intervals of time shall be recorded. The distance of depressed water level from the actual water table shall be obtained by the following formula: Ho = (H1)² / (H1 H2) Where, Ho = distance of depressed water level from actual water table, H1 & H2 = two successive rises of water level in the borehole for the same time interval. The water table depth (Hd) from ground level shall be determined as under: Hd = D Ho 4

5 Three sets of observation shall be made and the average value of Hd determined. Method (a) is suitable for permeable soil while methods (b) and (c) are suitable for both permeable and impermeable soils. The UNDP Engineer shall indicate the method to be followed. Immediately on completion of a borehole, bore log shall be prepared in an approved Performa and submitted to the UNDP Engineer in duplicate. Auger shall be used for soft to firm clay and for silty deposits at upper depths of 10 metres or up to the water table, whichever is deeper. For deeper depths in such deposits and for very stiff to hard clays and dense sands located at any depth, 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 casing diameter. This is to ensure that suction is not created in the borehole during withdrawal of the shell with consequent Caving-in and blowing in the boreholes Rotary Mud Circulation Drilling The drilling shall be carried out (as per IS: 1892) by use of a suitable mechanical rig. Drilling up to water table shall be done by auger and provisions of clauses to shall apply. Below the water table drilling by rotary mud circulation shall be adopted. Use of percussion tools may be permitted in very stiff to hard clays and dense sandy deposits only after obtaining written permission from Clients / Consultants Drilling in Rock In rock strata, boring shall be done by using a rotary cutting tool tipped with diamonds and equipped to recover cores. Drill hole size shall generally be NX. However, in some cases other size holes may be specified Core barrels shall be double-tube ball-bearing, swivel type, with the core lifter located in the lower end of the inner barrel. The Bidder shall confirm the same with 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 be necessary to secure the maximum possible amount of core. CONTRACTOR shall ensure that drilling is carried out with necessary skill and expertise 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 up to 6.5 to 7.0 m depth by cement grouting using Ax size drill, followed by drilling with 3½" casing Hx size drill or of a larger size. Initially about 1-1.5m depth shall be used, using Ax size drill, followed by 1:1 cement water grouting. After about hours of grouting, the boreholes shall be redrilled with casing itself (which may have a bit at the bottom or simple teeth). Further drilling shall then be carried out up to another m followed by grouting and redrilling. This sequence will be continued till m depth with every 1 m interval Backfilling of boreholes 5

6 On completion of boreholes, backfilling shall be carried out with an approved material as and when directed by the UNDP Engineer. Unless otherwise specified, the excavated soil shall be used for the purpose Termination Criteria If a very hard stratum is met within the borehole at depths shallower than specified in tender documents, the borehole shall be advanced by coring using double tube core barrel. The borehole may be terminated 3m below the depth where N > 75 values are obtained consistently. Coring the bore hole shall be burnt by contractor until UNDP Engineer Satisfaction enabled. 3.3 IN-SITU SAMPLING Trial Pits Trial pits shall be of minimum 3m x 3mX 3m size at base so as to permit easy access for a visual examination of the walls of the pit and to facilitate sampling and in-situ testing operations. Precautions shall be taken to ensure the stability of pit walls, if necessary by the provision of shoring. Arrangements shall be made for dewatering, if the pit is extended below water table. In-situ tests shall be conducted and undisturbed samples obtained immediately on reaching the specified depths, so as to avoid substantial moisture changes in the subsoil. After completion of tests and examination, the pits shall be suitably backfilled as directed by the UNDP Engineer. Unless otherwise specified, the excavated soil shall be used for this purpose Undistributed Soil samples from Boreholes Samples for recovering undistributed samples from cohesive soils at the specified depth shall conform to IS: However, use of samples less than 70mm diameter shall not be permitted. The sampling procedures shall conform to IS: Both the area ratio of the cutting edge, as well as recovery ratio of the sample shall be measured and reported. For normal soils, area ratio of the sampling tubes, shall conform to IS:2131, that is, it may vary from 10.9% to 12.4% but for sampling in very hard and dense soils, use of thick walled sampling tubes with area ratio not exceeding 20% may be permitted subject to the approval of the UNDP Engineer. In order to reduce the wall friction, suitable precaution such as oiling the inside and outside of the sampling tubes shall be taken. The sampling tube shall have smooth finish. In soft to firm clays, undisturbed samples shall be collected by pushing the tube continuously without impact or twisting. Driving of sampling tubes shall be permitted 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 of undisturbed 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 be tightly packed with saw dust or any other suitable material. A close fitting lid or screwed cap shall then be placed on each end of the tube and held in position by adhesive tape Core samples of rock The ease or difficulty of drilling at different depths shall be carefully noted and recorded during drilling. 6

7 The returning drill water shall be kept constantly under observation 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 feature is to be accurately determined, the length of the run shall be reduced to 1.0m unless directed otherwise by the ENGINEER. The core shall be removed from the drill hole immediately if blocking of the bit or grinding 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 drill hole other than water. For each run, Core Recovery and Rock Quality Designation (RQD) shall be noted carefully, immediately after cores are taken out of the barrel. Each and every core piece shall be serially and sequentially numbered from top downwards as soon as the core pieces are removed from the core barrel. The serial number shall be painted with good quality enamel paint. All core pieces shall be placed in core boxes in serial order in correct sequence from top downwards. Core boxes shall be made according to specifications laid down in IS: The cores, arranged in core boxes noted earlier, shall be submitted to the OWNER / ENGINEER on submission of the report Water Samples Water samples shall be collected from boreholes as specified. Water samples shall be collected before the addition of water to the hole unless that is not possible. If this is not possible, then prior to collection of water sample, water level in the bore hole shall be lowered up to the bottom of the borehole then allowed to rise by water seeping through the walls of the borehole. The water sample shall then be collected. Care shall be taken to see that water sample is not contaminated by surface water or rainwater. In some cases water samples may be required to be collected from different depths, if so specified. In such cases it is advisable to collect the samples on the completion of the relevant borehole unless a suitable sampler to collect water sample from different depths below free water surface is used. To collect the water 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. If specified, ground water sample shall also be collected from trial pits. If there are any wells within the area investigated, one water sample from each well shall also be collected. If specified, water samples shall also be collected from well (s) located nearby the area being investigated. The water sample shall be collected 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 Standard Penetration Test The test shall be conducted at specified intervals or at a depth where the strata changes, whichever occurs earlier. The test shall be carried out by driving a standard split spoon by means of 65 kg hammer with a 75 cm free fall. Detailed procedure of testing, as specified in IS: 'Method of Standard Penetration Tests in Soils' shall be followed. The samples obtained in the split spoon shall be labelled and preserved for identification tests in the laboratory. Standard penetration test shall be conducted at 1.5m interval. Sequence of conducting SPT shall be changed in each bore hole. Say for first bore hole SPT started at 1.5 m depth then 3.0 m,.. etc. 7

8 For next bore hole it shall be started at 1m depth then 2.5m etc. Similarly for other bore hole. So that staggered value of SPT s obtained for entire site. Disturbed samples to be collected (including packing and transporting) and sent to the Laboratory as per specifications. The standard penetration test shall be discontinued when N is greater than 75 blows for 30 cms of penetration 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 standard penetration value 'N' greater than 50. Test Procedures Test procedure shall meet the requirements of IS: 4968 (Part III). Some of the important points of the procedure are given below: a) The cone is pushed through a distance in accordance with the design of the equipment and the need for the sub-strata and the cone resistance noted. The cone and the friction jacket are pushed together subsequently for a distance depending upon the design of the cone and friction resistance noted. This procedure is repeated at predetermined intervals. b) Equipment shall be securely anchored to the platform at the test point for obtaining 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 sounding rod and the mantle tube. The assembly shall be positioned over the test point through the mantle tube guide and held vertically. The plunger of the driving mechanism shall be brought down so as to rest against the protruding 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 be operated at a steady rate of 1 cm / sec. approximately, so as to advance the cone only, to a depth which is possible with the cone assembly available. During the pushing, the mean value of resistance as indicated by pressure gauges shall be noted ignoring erratic changes. e) For finding combined cone and friction resistance of the soil, the sounding rod shall be pushed to the extent the cone has been pushed, at the rate of 1 cm / sec. noting mean resistance on the gauges. f) The above procedure shall be repeated after pushing the combined cone friction jacket and mantle tube assembly to the next depth at which the test is to be performed. g) The sequence of operation of the equipment shall be as per Fig. 5 of IS4968 (Part 3). The pro-forma for record of results of static cone penetration test shall be as approved by Consultants Vane Shear Tests These tests shall be conducted in soft to firm clays and sensitive clays. These tests shall also be conducted in case of stiff fissured clays where samples cannot be taken. Tests shall be generally conducted through boreholes. The apparatus used for vane shear tests shall satisfy the requirements as per IS:

9 For test from bottom of Borehole: a) Vane shall consist of four mutually perpendicular blades, as illustrated in IS: The height of the vane should be twice the blade diameter. It is recommended 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 little remoulding or disturbance as possible to the soil when inserted into the ground for a test. The blades shall be as thin as possible, consistent with the strength requirements. The vane should not deform under the maximum torque for which it is designed. The rotating edge of the vane blades shall be sharpened having an included angle of 90 deg. The vane blades shall be welded together suitably either directly or to a central rod, 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 not exceed 18% for the 37.5 mm vane and 12% for the 50, 65, 70 and 100 mm diameter vanes. The area ratio may be calculated using the following formula: Ar = [[8t (D-d) + πd²] / [πd2]] x 100 (%) Where Ar = area ratio in precent t = 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 the general soil conditions at a site. The vane rod (the rod to which the vane blades are fixed) may be enclosed in a suitably designed sleeve from just above the blades and throughout the length it penetrates the soil to exclude the soil particles and the effects of soil adhesion. This sleeve shall commence above the blades at 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 to the anchor casing and shall have an attachment to securely hold the string of rods connecting the vane. The instrument shall be capable of applying a torque to the vane through the 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. The torque applicator shall be provided with speed control so that the rate of rotation may be maintained at 0.1 deg. / sec. Friction exerted by the torque applicator shall be of negligible magnitude and shall be checked periodically. Depending upon the estimated shear strength of the soil the following table (Table 1) may be used as a guide for the selection of torque applicator of capacity 60 N.m (600 Kgf.cm). TABLE -1 SELECTION OF TORQUE APPLICATOR 10 (0.1) 20 (0.2) 30 (0.3) 40 (0.4) Estimated Shear Strength in KN/Sq.m (Kgf/sq.cm) Vane size (dia.) suitable for use with 600 Kgf. cm torque applicator All sizes All sizes except 100 mm size All sizes except 100 mm size All sizes except 75 mm size & 100 mm size 9

10 50 (0.5) 60 (0.6) 70 (0.7) All sizes except 75 mm size & 100 mm size 37.5 mm and 50 mm size 37.5 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 up to 60 N.m (600 kgf.cm) to an accuracy of 1 N.m (10 kgf.cm), or b) Measure torque up to 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 the torque applicator, called the rod system may be of quick coupling type or of the threaded type. The length of the rods shall be preferably 1m with a few of smaller lengths. These rods shall have sufficient diameter such that their elastic limit is not exceeded when the vane is stressed to its capacity (see Note 3). The threaded rods shall be so coupled that the shoulders of the male and female ends shall meet to prevent any possibility of the coupling tightening when the torque is applied during the test. If vane housing is used, the torque rods shall be equipped with well-lubricated bearings where they pass through the housing. These bearings shall be provided with seals to prevent soil from entering them. The torque rods shall be guided so as to prevent friction from developing between the torque rods and the walls of casing or boring. Note 3: If torque versus rotation curves to be determined, it is essential that the torque rods be calibrated (prior to the use in the field). The amount of rod twist (if any) shall be established in degree per metre per unit torque. This correction becomes progressively more important as depth of test increases. The calibration shall be made at least to the maximum depth of testing anticipated. d) Dummy Rod Of dimensions equal to that of the vane rod. e) Guides for Rod Of suitable type provided with ball bearing attachment so as to enable the rod to rotate freely (see Note 4). Note 4: During the test, it is essential that the rods and vane are placed centrally in the borehole. For this purpose guides shall be used at an interval in depth of not more than 5m. f) Drilling Equipment The equipment shall provide a clean hole of the required diameter for insertion of the vane to ensure that the vane test is performed on undisturbed 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 a) In addition the vane shall be suitably protected by a shoe. b) Rod System As specified in 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 10

11 As specified in 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 up to the depth required and extend the casing up to the full depth. If the casing is loose, secure it so that it does not move during the tests. Fix the torque applicator anchor plate to the casing. Connect the vane of suitable size (see Note 1) to the rods and lower it to the bottom of the bore-hole, put guides at suitable intervals but not more than about 5m as the rods are extended. Push the vane with a moderately steady force up to a depth of 5 times the diameter of the borehole below the bottom of the borehole or shoe. Take precaution to make sure that no torque is applied to the torque rods during the thrust. No hammering shall be permitted. Fix the torque applicator with frame to the anchor plate and connect the rods to it. Tighten the torque applicator to the frame properly. Allow a minimum period of 5 minutes after insertion of the vane. Turn the gear handle so that the vane is rotated at the rate of 0.1 deg / s. Note the maximum torque reading attained. If necessary, note the torque indicator dial gauge readings at half minute intervals and continue rotating the vane until the reading drops appreciably from the maximum. Just after the determination of the maximum torque, rotate the vane rapidly through a minimum of ten revolutions. The remoulded strength should then be determined (see C; above within one minute after completion of the revolutions). Remove the vane testing assembly, continue boring and collect soil sample from the level of the vane testing for laboratory analysis to ascertain whether the deposit will behave as a purely cohesive soil. In cases where a sleeve is not provided for the vane rod and the soil is in contact with the rod, determine the friction between the soil and the vane rod by conducting tests at appropriate depths using the dummy rod corresponding to that 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 in an 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 the vane 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 vane connected with rod is lowered to the bottom of boreholes. Vane shall be pushed with a moderate steady force up to a depth of five times the bore hole diameter below the bottom of boreholes. Precautions shall be taken to ensure that no torque is applied to the torque rods during the thrust. No hammering 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 until the vane readings drop appreciably from the maximum. d) Samples shall be collected from the levels at which the tests have been conducted. Tests by Direct Penetration from Ground Surface Rods shall remain tight when vane is lowered. Guides shall be placed at every 3m to centralise and reduce friction between rods and extension pipe. Records Records of vane test shall be maintained in approved pro-forma. 11

12 3.4.4 Electrical Resistivity Test This test shall be conducted as per Appendix B, Clause 3.2 of IS The test shall be done by using 4 points. The locations where ERT to be performed shall be finalized in consultation with EIC LABORATORY TESTS The following laboratory tests shall be conducted on samples collected from the field covering all the bores using procedures specified in the relevant Standards. All the Laboratory Tests shall be conducted by skilled personnel only Attenberg Limits The tests result should include liquid limit and plastic limit of the soil samples tested. These tests should be conducted as per IS: 2720 Part V Natural Moisture Content In case of organic soils, the oven temperature shall be 60 C and not 105 C Dry Bulk Density and Void Ratio Specific Gravity This test should be conducted as per IS: 2720, Part Grain Size Distribution Wherever applicable both the sieve and hydrometer analysis shall be conducted to indicate complete range of grain size in the soil sample tested. Generally, Hydrometer analysis will be carried out, wherever percentage passing No.200 sieve is greater than 30% Tri-axial Tests These tests shall be done on specimens saturated by the application of back pressure. Only if the water table is at sufficient depth so that chances of its rising to the base of the footing are meagre or nil, shall the tri-axial tests be performed on specimens at Natural Moisture Content. The magnitude of the backup pressure applied shall be indicated in the report. All stress diagrams as well as Mohr-circle envelopes shall be included in the report. E-value shall be determined from the tri-axial tests. Relevant corrections applied to the computer 'E' shall be clearly illustrated in the report Unconfined Compression Test This test shall be conducted as per IS: 2720, Part X Free Swelling Index This test shall be conducted as per IS: 2911, Part III Swelling Pressure Test This test shall be conducted as per Draft Standard circulated by Technical Committee on Expansive Soils (TC-6) of International Society of Soil Mechanics and Foundation Engineering; 'Evaluation of Swelling Pressure of Expansive Soil in Laboratory' (circulated in November, 1990). 12

13 Consolidation Tests The following loading stage shall be employed: 0, 0.1, 0.25, 1.0, 2.0, 4.0 and 8.0 kg / sq.cm. From e vs. log p curves, pre-consolidation pressure shall be determined to establish whether the soil is normally consolidated or over consolidated. The point (e, p) showing initial condition of the soil under test must be specifically marked on the consolidation curves. Settlement predictions based on the field virgin compression curve shall only be acceptable. The procedure adopted in respect of obtaining compression indices from the field curve and that for computing settlements for the type of clay under consideration shall be clearly illustrated in the report. It is to be noted that deviations from the standard procedure of performing consolidation tests given in IS:2720 are permissible in order to enable computation of settlements based on the above procedure i.e. cycles (s) of loading, 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 a clear determination of Cv, the coefficient of consolidation. The time period required for 50% and 90% primary consolidation should be given in the report. Computation of secondary settlements, if significant, shall also be made and included in the report Chemical Tests On Water & Soil Chemical tests shall be conducted on soil and water samples to report the following: a) ph b) Chloride c) Sulphate d) Sulphite e) Organic contents f) Total hardness Chemical Tests (Suitability of water for Construction) These tests shall be carried out to check suitability of water for construction purpose as required by IS: 456. Other Inorganic Tests as required by World Health Organisation (WHO) to test suitability for drinking purpose shall also be carried out CBR Tests for Sub-Grade soils (3 Point Tests) These tests shall be conducted on soaked and un-soaked samples generally as per IS: 2720 Part XVI. Bulk samples for laboratory tests shall be selected randomly from various road locations and also from locations of stacking areas in consultation with UNDP Engineer. The 3 point test shall consist of preparation of samples with 15, 25, 35 blows per layer, which will give three different densities to soil and then testing each for soaked condition Proctor Density Tests These tests shall be conducted as per IS: 2720 Part VII samples collected randomly in consultation with UNDP Engineer Levels & Co-Ordinates of Test Location 13

14 Contractor shall establish and tabulate reduced levels and co-ordinates of various test locations. Any expense on this account shall be deemed to have been included in the quoted rates. 3.6 REPORT Two copies of Draft\Interim Report shall be submitted to UNDP Engineer 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 UNDP 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 benchmark. 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 buildings. 10. Recommend suitable depth of foundation and foundation to be adopted for all buildings/pavements proposed at the given 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. Recommendations if water table location suggests use of Geo Textiles. 15. Comments on chemical aggressiveness of soil and ground water on reinforced concrete, steel and other building materials and firm recommendations on remedial/ preventive measures. 16. Recommendations of CBR value for design of 3 story Building (19mX84m), road, pavement etc. 17. Recommendation of soil resistivity to be considered for design purpose. 14

15 18. 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 2 Sets of Final Reports along with soft copy in CD. 15