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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 Experiment No. 1 1 2

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NAME OF EXPERIMENT DIRECT SHEAR TEST AIM To determine shear parameters ( c and ) of soil in under un-drained condition APPARATUS The shear box solid grid plates, base plates, loading pad, loading frame with slotted weights (0.2kg/cm2, 0.5kg/cm2 1kg/cm2 and 1.5kg/cm2, proving ring of 100kg to 250kg capacity, dial gauge 0.01 mm least count and stop clock. Loading frame 1000 kg capacity. Balance 0.1gm mim. Capacity. Spatula and straight edge.

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PREPARATION OF SPECIMAN Remoulded Specimens In case of Cohesion less density moisture contents are given. Based on these values weigh of dry soil is determined. The required moisture is added in the soil. The mould is assembled with base plate at bottom followed by solid serration plate (perpendicular to direction of shear force). The reference level is taken from the top of mould before samples is poured. The soil is then tamped in the shear box itself in layers till the difference in the layer shows 25 mm thickness of sample. The sample is then covered by solid serration plate similar to bottom plate and finally a loading pad is placed.

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THEORY: This test is also called as Box shear test. The sample is subjected two dimensional stresses such as normal stress in vertical direction and shear stress in horizontal direction (at constant rate). The test is useful for freely drained material (sands) since pore water pressure can not be measured. The main advantages of this test are that it is simple. The disadvantage of the method is it can-not controlled the drainage conditions hence; it is not suitable for fine grained soil. PROCEDURE Undrained Test The shear box with the specimen, plain grid plate over the base plate at the bottom of the specimen an ui7kd plain grid plate at the bottom top of the specimen is fitted into position into load frame. The upper part of the shear box should be raised such that a gap of about 1 mm is left between the two parts of the box. The required normal stress (0.2kg/cm2, 0.5kg/cm2 1kg/cm2 in individual trial) is applied and the rate of longitudinal displacement / shear stress application so adjusted (1.25

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Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

Received by Dr. S.B. Charhate H.O.D.

Approved by Dr. S.D. Sawarkar Principal

Issued by Dr.H.S. Chore M.R.

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010

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mm/min) that no drainage is occurred in the sample during the test. The test is now conducted by applying horizontal shear load to failure (indicated by decrease in proving ring reading) or to 20 percent longitudinal displacement, whichever occurs first. The shear load readings indicated by the proving ring assembly and the corresponding longitudinal displacements are noted at regular intervals (say 30 units). If necessary, At the end of the test, the specimen is removed from the box and the final moisture content is measured. A minimum of three (preferably four) tests shall be made on separate specimens of the same density. 6 CALCULATIONS Shear strain is expressed as, = Shear stress is given by, = proving ring reading. 7 RESULTS The shear parameters in the un-drained conditions are cohesion c = Angle of internal friction, = 8 DISCUSSIONS In case of sandy soil the c is close to zero and value is maximum. According to Terzaghi < 28 is classified as loose sand whereas, 380> > 28 is medium dense sand and 8 >38 is very dense sand. For saturated clays = 0 .0 0 0 0

L

100 , Where is shear displacement

F , where F is the maximum shear force calculated from A

PRECAUTIONS Select the proper capacity of proving ring. In any case PRR should not exceed maximum values given in calibration chart. No vibrations should be transmitted to the sample during the test and there should not be any loss of shear force due to friction between the loading frame and due shear box container assembly. The normal stresses to be selected for the test should correspond to the field conditions

and design requirements. Prepared by Received by V.B. Deshmukh Dr. S.B. Charhate Geotechnical Engineering H.O.D. Laboratory I/c

Approved by Dr. S.D. Sawarkar Principal

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010

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DATE OF SUBMISSION GRADE SIGNATURE

Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

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Approved by Dr. S.D. Sawarkar Principal

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 OBSERVATIONS DIRECT SHEAR TEST Density, g/cc Moisture content Drainage condition Max. Size of particle Area of sample, A = 36 cm2 Length of sample, L = 6 cm Volume, V = 90 cm3 DGR PRR Displacement mm =DGR x constant

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Date Proving ring capacity Proving ring number Proving ring factor C.F. Dial Gauge constant

Shear strain %= L 100

Shear Force, F= PRR x CF

Shear stress

=cm2

F kg/ A

0 0 30 60 Note: till PRR decreases or upto 20% strain whichever reaches earlier

Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010

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Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

Received by Dr. S.B. Charhate H.O.D.

Approved by Dr. S.D. Sawarkar Principal

Issued by Dr.H.S. Chore M.R.

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 Experiment No. 2 NAME 1 2 OF EXPERIMENT DETERMINATION

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OF

UNCONFINED

COMPRESSIVE STRENGTH AIM : To determine Undrained Cohesion of partly saturated clayey soil APPARATUS a) Split mould- Diameter 38 mm and Height 76 mm b) Seamless tubes -38 mm diameter and 50 mm height, 3 numbers. c) Pressure cell with central pedestal (cell pressure opening is closed) d) Proving ring (depending on stiffness of soil) e) Dial gauge for deformation measurement 0.01mm per unit to max. 25 mm travel f) Loading frame of 1t capacity, arrangement for application of different strain rate g) Solid plates with loading pad h) Vertical sampling ejector for transferring sample from UDS tube/ compaction mould into seamless tube. i) Horizontal ejector for transferring sample from seamless tube to mould. j) Miscellaneous Equipment Specimen trimming and carving tools, water content cans, etc, spatula, vernier caliper. Balances weighted to the nearest 0.01 g, whereas specimens of 100 g or larger shall be weighed to the nearest 0.1 g. k) Oven thermostatically controlled, with interior of non-corroding material, capable of maintaining the temperature at 110 + 50 C.

3. 3.1

PREPARATION OF TEST SPECIMEN The soil specimen to be used for test may be undisturbed, compacted or remoulded. Specimen size The specimen for the test shall have a minimum diameter of 38 mm and the largest particle contained within the test specimen shall be smaller than 1/8 of the specimen diameter. If, after completion of test on undisturbed sample, it is found that larger particles are present than permitted for the particular specimen size tested, it shall be noted in the repot of test data under remarks. The height to diameter ratio shall be 2. Measurements of height and diameter shall be made with Vernier calipers or any other suitable measuring device to the nearest 0.1 mm. Undisturbed Specimens The undisturbed is collected in UDS tubes from the site. The wax is removed and three seamless tubes are penetrated with help of vertical extractor. The sample is then pushed Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

3.2

Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

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into mould by horizontal extractor. The projected sample in the mould is then trimmed in order to make either surfaces of sample perfectly perpendicular to axis of mould. The split mould is then opened and sample removed by pushing solid plates on either sides of specimen. The mass and dimensions are measured and sample is assembled in the pressure cell. Representative sample cuttings shall be used for the determination of water content. Remoulded Specimen The dry density and moisture content are given or obtained from proctor test to evaluate dry mass of soil and moisture content. The known quantity of mixed soil sample is then compacted into proctor mould statically or dynamically. The three seamless tubes are pushed vertically in the mould by vertical extractor. The sample of size 38 mm diameter and 76 mm height is obtained by pushing sample from seamless tube into mould in horizontal extractor. 4. THEORY Unconfined compression test is a special tri-axial test. It is used when the soil to be tested is a saturated clay and = 00 condition prevails in the field. This test is similar to triaxial compression test except cell pressure is zero. Hence, only one Mohrs is required for 5. determination of cu. The figure shows Mohrs circle and failure envelope. PROCEDURE The specimen is placed on the central pedestal of cell. The top and bottom of the sample covered with solid plate and loading pad on top solid plate. The cell cover is closed and plunger is made in contact loading pad. The Dial (deformation) gauge and proving ring (force measurement) are assembled on the loading frame. The deformation dial gauge and proving ring are adjusted to zero. Force shall be applied so as to produce axial strain at a rate of 1/to 2 percent per minute. Force and deformation readings are recorded at suitable intervals (usually 30 on dial gauge). The specimen is compressed until failure surfaces have definitely developed or the stressstrain curve is well past or until an axial strain of 20 percent is reached. The failure pattern is sketched carefully and shown on the data sheet or on the sheet presenting the stress-strain plot. The water content of the specimen is determined in accordance with geotechnical engineering manual I using samples taken from the failure zone of the specimen. 6. CALCULATIONS Stress-Strain values shall be calculated a follows: Prepared by Received by Approved by V.B. Deshmukh Dr. S.B. Charhate Dr. S.D. Sawarkar Geotechnical Engineering H.O.D. Principal Laboratory I/c

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a) The axial strain, %, is determined is expressed as=L 100 L0

Where, L = the change in the specimen length as read from the strain dial indicator, and L0 = the initial length of the specimen. b) The average cross-sectional area, A, at a particular strain shall be determined from the following relationship:A= Ao L 1 L0

Where, A0 = the initial average cross-sectional area of the specimen c) Compressive stress, c, shall be determined from the relationshipc =P A

Where, P is the compressive force kg, and A = average cross-sectional area, cm2 Values of stress c, and strain, %, obtained from above calculations are plotted on abscissa and ordinate respectively. The maximum stress from this plot gives the value of the unconfined compressive strength, qu. 7. RESULTS The unconfined compression strength qu The un-drained cohesion cu DISCUSSION The failure plane is 450 if = 00 for fully saturated clay sample otherwise it is partly saturated or particles oversize 2mm. Proving ring reading and dial gauge reading are recorded within their limits as referred from calibration chart. The selection of capacity of proving ring depends on stiffness of sample. The basic physical properties also indicated the approximate strength. During the preparation and assembling of the sample a care must taken reduce the Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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disturbances. DATE OF SUBMISSION GRADE SIGNATURE

Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 OBSERVATION TABLE UNCONFINED COMPRESSION TEST 1. Details of the soil specimen: i. Undisturbed or remoulded or compacted: ii. Initial diameter, D0 iii. Initial length, Lo iv. Initial area, A0 v. Initial mass of the specimen vi. Initial density vii. Initial water content 2. Proving Ring No. 3. Proving ring capacity 4. Proving ring factor, C 5. Dial Gauge Constant ,G DGR PRR Compressive Force in kg PRR x CF (3) Deformation L = DGR x G mm (4) Strain in % 100L/L0 (5) mm mm cm2 g g/cm2 %

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Area A in cm2

Compressive Stress qu in kg/cm2 (7)

(1) (2) (6) 0 30 60 Note: Test is continued till PRR decreases or 20% whichever earlier

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Figure Schematic diagram showing sample in unconfined compression test

Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 Experiment No. 3 1 2

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NAME OF EXPERIMENT TRI-AXIAL COMPRESSION TEST AIM Determination of the shear strength parameters of a partly saturated sample in Unconsolidated Undrained Triaxial Compression without the measurement of pore water Pressure. IS: is referred for the procedure. APPARATUS Split Mould 36 mm diameter and length 72 mm. Trimming knife sharp-bladed, for example, a spatula or pallet knife. Metal Straightedge Metal Scale Non-Corrodible Plastic End-Caps of the same material as the test specimen. The upper end cap is to have a central spherical seating to receive the loading ram (see Note). A solid plastic end cap, 20 mm thick, is normally satisfactory for use on soft or very soft soils. Seamless tubes in the form of a steel tube, open at both ends of internal diameter 36mm and of length 50 mm. The Rubber Membrane- the thickness should be selected having regard to the size, strength and nature of the soil to be tested. A thickness of 0.2 to 0.3 mm is normally satisfactory. Membrane Stretcher steel tube 38 mm diameter with rubber tube in the middle to for suction. Rubber Rings of circular cross-section stretchable to suit the 36 mm diameter of the end caps. Apparatus for Moisture content Determination as described in Geotechnical engineering I manual. Balance readable and accurate to 0.1g Vertical Extruders - to transfer sample from UDS tubes / compaction mould into seamless tubes. Horizontal Extruder- It is a table mounted arrangement to push the sample from seamless tubes into split mould. Triaxial Test Cell A transparent chamber to withstand the maximum pressure of 10 kg/cm2 and provided with a plunger for applying additional axial compressive load to the specimen by means of a loading ram. is recommended. The base of the cell is provided with a suitable central pedestal with drainage outlets with valves. Cylinder with pressure gauge for applying and maintaining the desired pressure on the Fluid within the Cell to an accuracy of 0.1 kg/cm2 with a gauge for measuring the pressure. The cylinder is filled with 2/3 of volume by water. Loading frame - For Applying Axial Compression to the Specimen 1 t loading capacity

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Note:

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and operate at convenient speeds to convert the range 0.05 to .5 mm per minute. Proving ring- 100 kg capacity with sensitivity of 0.2 kg for low strength soils and one of 1000 kg capacity with sensitivity of 1 kg for high strength soils. Dial Gauge 0.01 mm least count with provision for maximum compression of 25 mm is 4. 4.1 used. PREPARATION OF SPECIMENS Undisturbed Specimens The object of specimen preparation is to produce cylindrical specimens of height twice the specimen diameter with a plane ends normal to the axis and with the minimum change of the soils structure and moisture content. A specimen from a sampling tube of the same internal diameter as the required specimen may be obtained as given in (a) to (e). a) A UDS sample is cut from the site with and sealed with wax on either sides b) The wax, used for sealing, is removed and the cutting edge end of the sample smoothed so that it is approximately normal to the axis of the tube. Three seamless tubes are pushed vertically into UDS tube which is held in vertical extruder. All seamless tubes are cut from the UDS sample by rotating and lifting vertically. c) The horizontal extruder is then used to push the each sample through the seamless tube into split mould. The sample is leveled and then removed by opening split moulds. d) The length, diameter and weight of the specimen is measured to an accuracy enabling the bulk density to be calculated to an accuracy of + 1.0 percent. e) The specimen is placed on one of the end caps and the other end cap is put on top of the specimen. The rubber membrane shall then be placed around the specimen using the membrane stretcher and the membrane sealed to the end caps by means of rubber rings. f) The specimen is then ready to be placed on the pedestal in the Triaxial cell. The pedestal 4.2 covered with a solid end cap or the drainage valve is kept closed. Remoulded Samples a) The dry weight of soil and quantity of water are calculated from the given density and moisture. The soil mixed with moisture contained is then compacted in compaction mould by dynamic or static method. The sample is then cut in three seamless tubes using vertical extractor and finally pushed into mould by horizontal extractor. Follow the procedure in (c-f). 5 THEORY Prepared by Received by Approved by Issued by V.B. Deshmukh Dr. S.B. Charhate Dr. S.D. Sawarkar Dr.H.S. Chore Compiled Geotechnical Engineering H.O.D. Principal M.R. copy if stamp Laboratory I/c is red colour

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Tri-axial test overcomes demerits of box shear test. It is more advantageous due measurement of volume change during test and state of stress at any time during testing. Unconsolidated Undrained test is performed immediately the applying the confining pressure. The failure loading is applied to the sample so rapidly that no pore water pressure can drain or escape from the specimen during the test. The test will be always produce a value of of 00 for saturated cohesive soils, this is often describe as = 00 condition. The choice of drainage condition depends on drainage condition expected in the site. If the soil is sandy, excess pore pressure resulting from the new load usually expected to dissipete rapidly and drained condition should be expected. If the soil is stressed in the field is saturated clay, excess pore pressure dissipates slowly and = 00 condition governs: thus a UU test is the proper choice. The UU test is often called a quick test (Q test) because it can be performed quickly compared to the other two types of loading and drainage tests. It is usually completed in 30 6. minutes per specimen. TESTING PROCEDURE The specimen prepared as described above is placed centrally on the solid circular plate in top and bottom which is finally rest on the pedestal of the Triaxial cell. The cell is assembled with the loading ram resting on solid plate and load pad. The cell containing the specimen is placed in the loading machine. The operation fluid is admitted to the cell from cylinder and the pressure is raised to the desired value. The proving ring and dial gauges are installed at their appropriate locations. The loading machine is then further adjusted to bring the loading ram just in contact with the seat on the top cap of the specimen and the initial reading of the gauge measuring the axial compression of the specimen shall be recorded. A rate of axial compression is selected (Gear No.1) such that failure is produced within a period of approximately 5 to 15 minutes. The test commenced with a sufficient number of simultaneous readings of the proving ring and dial gauge are taken to define the deviator stress-axial strain curve. The test is continued until the maximum value of the stress has been passed or until an axial strain of 20 percent has been reached. Note: - It is often convenient to make a plot of load versus compression as the test proceeds, to Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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enable the point of failure to be determined. The cell is drained of fluid, dismantled and the specimen taken out. The rubber membrane is removed from the specimen and the mode of failure shall be noted (see Note 1). The specimen is weighed (see Note 2) and samples for the determination of the moisture content of the specimen is taken [see Geotechnical Engineering Manual I]. If there is a moisture change in the specimen, it should be recorded and discretion used with regard to acceptability of the test. Note 1: - The most convenient method of recording the mode of failure is by means of a sketch indicating the position of the failure planes. The angle of the failure plane (s) to the horizontal may be recorded, if required. These records should be completed without undue delay to avoid loss of moisture from the specimen. Minimum three samples are tested at higher cell pressure (usually twice the earlier pressure). Note 2 Comparison with the recorded weight of the specimen before testing provides a check on the impermeability of the rubber membrane if water has been used as the operating fluid in the cell. 7. CALCULATIONS Stress-Strain values shall be calculated a follows: d) The axial strain, %, is determined is expressed as=L 100 L0

Where, L = the change in the specimen length as read from the strain dial indicator, and L0 = the initial length of the specimen. e) The average cross-sectional area, A, at a particular strain shall be determined from the following relationship:A= Ao L 1 L0

Where, A0 = the initial average cross-sectional area of the specimen f) Deviator stress, d, is determined from the relationship Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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d =Where,

Wd A

Wd is the compressive force kg, and A = average cross-sectional area, cm2 8. g) The major principal stress is expressed as, 1 = d + 3 where, 3 is minor cell pressure. RESULTS The undrained cohesion cu = 9 Angle of Internal Friction = PRECAUTION Proving ring reading and dial gauge reading are recorded within their limits as referred from calibration chart. The elastic membrane must dry and dusted in power in order to reduce the friction. The selection of capacity of proving ring) depends on stiffness of sample. The basic physical properties also indicated the approximate strength. During the preparation and assembling of the sample a care must taken reduce the disturbances. DATE OF SUBMISSION GRADE SIGNAURE

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 OBSERVATIONS TRIAXIAL COMPRESSION TEST Specimen preparation procedure Initial length of specimen, L Initial diameter of sample, d Initial Area of sample, Proving ring No. Proving ring capacity Mode of failure Angle of failure plane with vertical Cell pressure 3 = .. kg/ cm2 Dial gauge Reading (DGR) Proving Ring Reading (PRR) l = DGR x Strain % C= lL 100

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Bulk Density,g/cm3 NMC Rate of strain Dial gauge least count C Sketch of specimen after failure

Ao

Initial weight of specimen

Deviator Load Wd = PRR*CF

Corrected AreaAf = A0 1

Deviator Stress, kg/cm2dWd Af

lL

100

Note: CF = Refer calibration chart From the stress-strain curves principle stresses are evaluated as Sample No. Maximum deviator stress, dmax kg/cm2 Cell pressure 3, kg/cm2 Major principal stress, 1,= 3,+ dmax kg/cm2 1 2 3

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 Experiment No 4 NAME OF EXPERIMENT CONSOLIDATION TEST AIM

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1

To determine the compressibility parameters i.e. coefficient of consolidation (cv) , coefficient of compressibility (av) , compression index (cc) , coefficient of volume change (mv) and 2. 2.1 preconsolidation pressure (pc). APPARATUS Consolidating Ring The diameter of ring 60 mm and 20 mm thick. The ring is rigid and made of a material which is non-corrosive. The inner surface is smooth and highly polished. The ring shall be provided with a cutting edge in order to facilitate preparation of specimens. The height of the ring shall not be less than 20mm with a diameter to height ratio of about 3.0 and further the specimen height shall be not less than 10 times the maximum particle 2.2 size. Porous Stones These stones are placed at the top and bottom of the soil specimen, and shall be of silicon carbide, aluminum oxide or other porous materials not attacked by the soil. The porosity of the stones are such that free drainage is assured throughout the test, but that no intrusion of soil into the pores of the stones takes place. A sheet of Whatman No. 54 filter paper of diameter equal to that of the stone, may be placed 2.3 between the stone and the soil surface in order to prevent intrusion. Consolidation Cell A container within which is placed the consolidation ring containing the specimen between the top and bottom porous stones. The cell is capable of being filled with water to a level higher an axial vertical load applied to the top of the specimen and of 2.4 2.5 allowing measurement of the change in height of the specimen on its central axis. Dial Gauge The gauge that read to an accuracy of at least 0.01 percent of the specimen height and have a travel of at least 50 percent of the specimen height. Loading Device A device which enables vertical force to be applied axially in suitable increments, to the test specimen, through a suitable loading yoke. The force is applied to the loading cap of the specimen centrally through some form of spherical seating. The applied load is known to an accuracy of at least + 1percent. The loading device permits application of a load increment within a period of 2 s without Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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significant impact. Trimming Equipment Metal straightedge, thin bladed trimming knife (like spatula). Equipment for Measuring Initial Height of Test Specimen to Accuracy of 0.1 mm Vernier reading calipers. Moisture Content Containers and Drying Air-Oven Maintained at 110 + 50C, Desiccator. Balance Sensitive to 0.01 g For weighing the specimen and moisture content. Stop watch readable to 1 s. 3. THEORY Every structure resting on soil settles therefore, compressibility is the important physical property. It is the dependent properties. Compressibility of soil is related to magnitude of settlement and time of settlement. The experimental determination is based on one dimensional consolidation that takes place along vertical direction of saturated compressible soil. The coefficient compressibility Cv indicates the time required for settlement of foundation. The compression index Cc, coefficient of volume change mv, determines the magnitude of settlement. The types of clay deposits depends on the magnitude of preconsolidation pressure pc whereas 1-Dimensional consolidation is is similar to permeability hence, an approximate value of coefficient of permeability is also determined. The Darcys law is valid and sample is fully saturated before it is consolidated. This test consolidates the undisturbed soil but can be extended to compacted soil. 4. 4.1 PROCEDURE Preparation of Test Specimen Determine the weigh the empty consolidation ring (W1). If the specimen is prepared from a UDS sample, a representative sample for testing is extruded and cut off, care is taken to ensure that the two plane faces of the resulting soil disc are parallel to each other. The thickness of the disc of soil shall be somewhat greater than the height of the consolidation ring. The consolidation ring with cutting edge is gradually inserted into the sample by pressing with hands and carefully removing the material and the ring. The consolidation ring is sometimes pushes along with a guide ring placed on the top. The surrounding of sample is loosened by spatula and entire assembly is cut at bottom. The soil sample thus obtained is trimmed flush with the top and bottom edges of the ring. For soft to medium soils, excess soil should be removed using a wire saw and final trimming Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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may be done with a straight edge, if necessary. For stiff soils, a straight edge alone is used for trimming. Excessive remoulding of the soil surface by the straight edge should be avoided. In the case of very soft soils, special care should be taken so that the specimen may not fall out of, or slide inside the ring during trimming. A sample of soil similar to that in the ring. Taken from the trimming, is used for determining moisture content. The thickness of the specimen (H0) shall be measured and weighed immediately (W2). Assembly of Apparatus The bottom porous stone are centered on the base of the consolidation cell When testing softer, normally consolidated clays, the porous stones are made wet and covered by a wet filter paper The ring and specimen are placed centrally on the bottom porous stone and the upper porous stone, and then the loading cap are placed on top. A small water chamber with head of water equaled to mid height of sample is connected at the bottom of consolidometer. In new type of consolidometer spce between the cell and outside boundary is filled with water. The consolidometer is placed in position in the loading device and suitably adjusted. The dial gauge is then clamped into position for recording the relative movement between the base of the consolidation cell and the loading cap. A seating pressure of 0.05 kgf/cm2 is applied to the specimen. The specimen shall then be allowed to reach equilibrium for 24 h. 4.3 Loading For consolidation testing, it is generally desirable that the applied pressure at any loading stage be double than at the preceding stage. The test may therefore be continued using a loading sequence which would successively apply stress of 0.1, 0.2, 0.4, 0.8, 1.6, 3.2 and 6.4 kgf/cm2, etc, on the soil specimen. For each loading increment, after application of load, readings of the dial gauge are taken using a time sequence such a 0, 0.25, 1, 2.25, 4, 6.25, 9, 12.25, 16, 20.25, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, min, etc, up to 24 h or 0, , , 1, 2, 4, 8, 15, 30 and 60 min, and 2,4,8 and 24 h. These time sequences facilitate plotting of thickness or change of thickness of specimen against square root of time or against log time. The loading increment is left at least until the slope of the characteristic linear secondary compression portion of the thickness versus log time plot is apparent, or until the end of primary consolidation is indicated on a square root of time plot. A period of 24 h will usually Prepared by Received by Approved by Issued by V.B. Deshmukh Dr. S.B. Charhate Dr. S.D. Sawarkar Dr.H.S. Chore Compiled Geotechnical Engineering H.O.D. Principal M.R. copy if stamp Laboratory I/c is red colour

4.2

Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010

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be sufficient, but longer times may be required. If 24 h are seen to be sufficient, it is recommended that this commonly used load period be used for all load increments. In every case, the same load increment duration is used for all load increments during a consolidation test. It is desirable that the final pressure be of the order of at least four times the preconsolidation pressure, and be greater than the maximum effective vertical pressure which will occur in-situ due to overburden and the proposed construction. On completion of the final loading stage, the specimen is unloaded by pressure decrements which decrease the load to of the last load. Dial gauge readings are taken as necessary to proceed much more rapidly (after every 2 hours.) On completion of this decrement, the water shall be siphoned out of the cell and the consolidometer is quickly dismantled after release of the final load. The specimen, preferably within the ring, is wiped free of water, weighed (W3) and thereafter placed in the oven for drying. If the ring is required for further testing, the specimen may be carefully removed from the ring in order to prevent loss of soil, and then weighed and dried. Following drying, the specimen with ring is reweighed (W4). The specific gravity of the sample is determined at the end. 5. 5.1 CALCULATIONS Coefficient of consolidation, cv The coefficient of consolidation, cv, for the load increment under consideration may be calculated from the formula:

0.848 ( H av ) Cv = t 90Where,

2

Hav is the average specimen thickness for the load increment

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 5.2 Engineering Department) Date: 1 January 2010

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Relation between void ratio e and effective pressure Methods i) ii) Change in void ratio method and Equivalent height of solid method

In change in void ratio method Change in height after every increment of effective pressure H is given asH = H 0 H

Whereas, H mm= (Final DGR-Initial DGR) and Ho is the original height of sample Final void ratio, ef is given bye f =w f G

Where, wf is the final moisture content at the end of consolidation Change in void ratio e is given ase =

(1 + e )f

Hf

H

The coefficient of compressibility, av 5.3 From the plot of the void ratio, e versus , the slope of the straight line portion that is for the soil in the normally consolidated state is designated as Coefficient of compressibility, av cm2/kg is given byav = e

5.4

Compression Index, Cc From the plot of the void ratio, e versus log . The slope of the straight line portion that is for the soil in the normally consolidated state is designated as Cc. This can be directly obtained from the plot or calculated as:Cc = e log 2 1

5.5

Coefficient of volume change Received by Dr. S.B. Charhate H.O.D.

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5.6 5.7

Coefficient of Permeability Kk = c v mv w

Coefficient of Permeability Kk = c v mv w

6.

RESULTS Applied pressure coefficient of consolidation, cv coefficient of compressibility av compression index cc coefficient of volume change mv preconsolidation pressure pc Approx. coefficient of permeability, k Initial void ratio, e DISCUSSIONS The pressure increment (effective stress) depends on actual effective overburden stress at site. The increment varies from 60% to 200% of that effective overburden pressure. In case of stiff clay pressure increment may be may starts from 0.2 kg/cm2 to 8 kg/cm2 but in no case it exceeds ultimate bearing capacity. PRECAUTIONS The porous stones used for drainage should be saturated for 48 hrs and boiled for at least half an hour before used in the test. The use of oil is strictly not recommended during the cutting and leveling of the sample. The sample preparation is skilled process at least disturbances are allowed during the preparation. The spatula used in cutting / leveling the sample must be wet each time before touch to the sample. The set up should be free from any shocks, vibrations and direct access to outsiders. DATE OF SUBMISSION GRADE SIGNAURE

7

8

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D ia l G a u g e

s a m p le

P o ro u s S to n e s

S a tu r a tio n ta n k

Figure : Cross-section of Odometer

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 OBSERVATIONS CONSOLIDATION TEST

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Project Sample No. Soil Identification . Specific gravity . Specimen preparation Procedure Type of water used

Specimen measurements Diameter D = cm Area A = D2/4 .. cm2 Thickness H0 = . Cm Wt. of ring (W1) = g Wt. of specimen + ring (W2) = .. g Final wt. of specimen (W3) = . Dry wt. of specimen + ring (W4) .. g Density = .. g/cm3

Water content Can no. = Wt. of can + wet soil = g Wt. of can + dry soil = g Wt. of can = .g Wt. of water = ............. g Wt. of dry soil = .. g Water content, percent =

Consolidation test: pressure increment data

Date

Time elapsed, min

Dial Gauge Reading

DGR

Remarks

Loading0.1kg/ cm2

0.2 kg/cm2

0.4 kg/cm2

0.8 kg/cm2

1.6 kg/cm2

3.2 kg/cm2

6.4 kg/cm2

Unloading 6.4kg/cm2

Unloading readings Are recorded every two hrs

1.6kg/cm2 0.4kg/cm2 0.1kg/cm2

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Relation between void ratio e and effective pressure

Hf = Applied Pressure (kgf/cm2) (1)

e f =w f G

e =

(1 + e )f

Hf

H

Final Dial Reading

Compression H (mm)= Diff. in successive final DGR (3)

Specimen height H (cm)= H0 -H

e

Void Ratio e

Remarks

(2)

(4) Last reading Hf =

(5)

(6)

(7)

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 Experiment No 5

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1 2. 2.1

NAME OF EXPERIMENT : VANE SHEAR TESTS AIM To determine shear strength of saturated clay with referenced to IS 2720 Part (30)1980 APPARATUS Vane The vane consist of four blades each fixed at 900 to the adjacent blades as illustrated. It should not deform under the maximum torque for which it is designed. The penetrating edges of vane blades are sharpened having an included angle of 90 0. The vane blades are welded together suitably to a central rod, the maximum diameter of which should preferably not exceed 2.5 mm in the portion of the rod which goes into the specimen during the test. The vane is properly treated to prevent rusting and corrosion.

2.2

The frame: The apparatus maybe either of the hand-operated type or motorized. Provisions should be made in the apparatus for the following: a) Fixing of vane and shaft to the apparatus in such a way that the vane can be lowered gradually and vertically into the soil specimen. b) Fixing the tube containing the soil specimen to the base of the equipment for which it should have suitable hole. c) Arrangement for lowering the vane into the soil specimen (contained in the mould fixed to the base) gradually and vertically, and for holding the vane properly and securely in the lowered position. d) Arrangement for rotating the vane steadily at a rate of approximately 1/60 rev/min (0.10/s) and for measuring the rotation of the vane. e) A torque applicator to rotate the vane in the soil and a device for measuring the torque applied to an accuracy of 0.05 cm. kgf. A typical form of the hand/motorized apparatus is shown in Figure. Graduated circle calibrated 0-3600 Mould : Diameter 30 mm and Height 70 mm Spring: Stiffness varying from 2kg/cm2 to 8kg/cm2 THEORY

3.

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Laboratory vane shear test is used for soft saturated clayey (cu= 12.5 kN/m2) soil which is difficult to withstand the self weight. This is kind of test where failure of sample is due to torque application. 4. PROCEDURE The specimen in the tube should be at least 30 mm in diameter and 75 mm long. If the specimen container is closed at one end, it should be provided at the bottom with a hole of about 1 mm diameter. Cut the undisturbed specimen and find out the density and small sample for NMC. Mount the specimen container with specimen on the base of the vane shear apparatus and fix it securely to the base. Lower the shear vanes into the specimen to their full length gradually with minimum disturbance of the soil specimen so that the top of the vane is at least 10 mm below the top of specimen. Note the readings of the strain and torque indicators. Rotate the vane at a uniform rate approximately 0.10/s by suitably operating the torque applicator handle until the specimen fails. Note the final reading of the torque indicator. Torque readings and the corresponding strain reading may also be noted at desired intervals of time as the test proceeds. Just after the determination of the maximum torque, rotate the vane rapidly through a minimum of ten revolutions. The remoulded strength is then be determined within 1 minute after completion of the revolution. 5. CALCULATIONS Un-drained shear strength kg/cm2Su = T H d d 2 + 2 6

Where, T is the torque kg-cm d is the diameter of vane in cm H is the height of vane in cm Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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( S u ) undistrubed ( S u ) remoulded

The cu determined from above results shows ..clay. The sensitivity for marine clay obtained from Thane creek shows 5-12. 8 PRECAUTIONS It is important that the dimensions of the vane are checked periodically to ensure that the vane is not distorted or worn out. DATE OF SUBMISSION GRADE SIGNAURE

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Figure : Typical hand/motorized vane shear apparatus

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Figure: Details of vanes attached to vane rod

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Department : Civil Engineering Name of the Process: (Smooth and effective working of Civil Issue No: 01 Engineering Department) Date: 1 January 2010 OBSERVATIONS VANE SHEAR TEST Bulk Density, kg/cm2 NMC Diameter of Vane, D Height of Vane, H Spring Factor, K kg-cm A) Undisturbed Shear Strength Sr. No. Initial Reading degree 1 2 Final Reading degree Difference Torque T in radians

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Shear Strength Su kg/cm2

=Difference x K

Average undisturbed shear strength Su kg/cm2 B) Remoulded Shear Strength Sr. No. Initial Reading degree 1 2 Average disturbed shear strength Su kg/cm2 Final Reading degree Difference Torque T in radians =Difference x K Shear Strength Su kg/cm2

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NAME OF EXPERIMENT- CALIFORNIA BEARING RATIO TEST 1 AIM Laboratory determination of California Bearing Ratio at un-soaked condition. 2 APPARATUS Moulds with Base Plate: 150 mm diameter and 175 mm in height and base plate of 235 mm diameter. Stay Rod and Wing Nut - Spacer Disc, Metal Rammer, Weights Loading Machine - With a capacity of at least 5 000 kg and equipped with a movable head or base which enables the plunger to penetrate into the specimen at a deformation rate of 1.25 mm/min- The machine is equipped with a load device that can read to suitable accuracy. Penetration Plunger: 50 mm diameter and height of 50 mm with hole for connection Dial Gauges - Two dial gauges reading to 0.01 mm least count Sieves 4.75 mm and 19 mm IS sieves Miscellaneous Apparatus - Other general apparatus, such as a mixing bowl, straightedge, scales, soaking tank or pan, drying oven, filter paper, dishes and calibrated measuring jar. Surcharge weights 2.5 kg annular weights of two numbers 3 PREPARATION OF SPECIMEN The dry density for a remoulding is either the field density or the value of the maximum dry density estimated by the compaction tests or any other density at which the bearing ratio is desired. The water content used for compaction is the optimum water content or the field moisture as the case may be. Soil Sample - The material used in the remoulded specimen passes a 19-mm IS Sieve. Allowance for larger material is made by replacing it by an equal amount of material which passes a 19-mm IS sieve but is retained on 475-mm IS Sieve. Statically Compacted Specimens - The mass of the wet soil at the required moisture content to give the desired density when occupying the standard specimen volume in the mould shall be calculated. A batch of soil shall be thoroughly mixed with water to gives the required water content. The correct mass of the moist soils is placed in the mould and Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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compaction obtained by pressing in the displacer disc, a filter paper being placed between the disc and the soil. Dynamically Compacted Specimen - For dynamic compaction, a representative sample of the soil weighing approximately 4.5 kg or more for fine-grained soils and 5.5 kg or more for granular soils is taken and mixed thoroughly with water. If the soil is compacted to the maximum dry density at the optimum water content the exacta mass of soil required is taken and the necessary quantity of water added so that the water content of the soil sample is equal to the determined optimum water content. The mould with the extension collar attached shall be clamped to the base plate. The spacer disc shall be inserted over the base plate and a disc of coarse filter paper placed on the top of the spacer disc. The soil-water mixture shall be compacted into the mould. The extension collar is then removed and the compacted soil carefully trimmed even with the top of the mould by means of a straightedge. Any hole that may then, develop on the surface of the compacted soil by the removal of coarse material, is patched with smaller size material; the perforated base plate and the spacer disc are removed, and the mass of the mould and the compacted soil specimen recorded. A disc of coarse filter paper shall be placed on the perforated base plate, the mould and the compacted soil is inverted and the perforated base plate clamped to the mould with the compacted soil in contact with the filter paper. 4 THEORY The potential soil subgrade is assessed by CBR method. It is used for design of thickness of pavement. Lower the CBR value indicates poor subgrade and hence, higher the thickness required. The CBR value of a soil is considered to be an index which in some fashion is related to its strength. The value is highly dependent on the condition of the material at the time of testing. Recently, attempts have been made to correlate CBR values to parameters like modulus of subgrade reaction, modulus of resilience and plasticity index, with considerable success. The load settlement curve (standard curve) for perfectly contacted plunger and error curve (modified curve) are shown in following figure. Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R.

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The standard load at various penetration are given as Penetration mm 2.5 5 5 PROCEDURE Penetration Test (see Figure) - The mould containing the specimen, with the base plate in position but the top face exposed, is placed on the lower plate of the testing machine. Surcharge weights, sufficient to produce an intensity of loading equal to the weight of Prepared by V.B. Deshmukh Geotechnical Engineering Laboratory I/c Received by Dr. S.B. Charhate H.O.D. Approved by Dr. S.D. Sawarkar Principal Issued by Dr.H.S. Chore M.R. Standard load, kg 1370 2055 Standard pressure kg/cm2 70 105

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the base material and pavement are placed on the specimen. The plunger is seated under a load of 4 kg so that full contact is established between the surface of the specimen and the plunger. The load and deformation gauges are then be set to zero. Load is applied to the plunger into the soil at the rate of 1.25 mm per minute. Reading of the load are taken at penetrations of 0.5, 1.0, 1.5, 2.0, 2.5, 4.0, 5.0, 7.5, 10.0 and 12.5 mm (The maximum load and penetration is recorded if it occurs for a penetration of less than 12.5 mm). The plunger shall be raised and the mould detached from the loading equipment. About 20 to 50 g of soil shall be collected from the top 30 mm layer of the specimen and the water content determined. The penetration test may be repeated as a check test for the rear end of the sample. 6 CALCULATIONS California Bearing Ratio - The CBR values are usually calculated for penetrations of 2.5 and 5 mm. Corresponding to the penetration value at which the CBR values is desired, corrected load value are taken from the load penetration curve and the CBR calculated as follows:C .B.R. = PT 100 Ps

PT =corrected unit ( or total ) test load corresponding to the chosen penetration from the load penetration curve, and PS =unit (or total) standard load for the same depth of penetration as for Pr taken from the table presented above. 7 RESULTS The CBR at 2.5 mm penetration The CBR at 5 mm penetration 8 Design CBR DISCUSSIONS Generally, the CBR value at 25 mm penetration will be greater than that at 5 mm penetration and in such a case, the former shall be taken as the CBR value for design purposes. If the CBR value corresponding to a penetration of 5 mm exceeds that for 2.5 Prepared by Received by Approved by Issued by V.B. Deshmukh Dr. S.B. Charhate Dr. S.D. Sawarkar Dr.H.S. Chore Compiled Geotechnical Engineering H.O.D. Principal M.R. copy if stamp Laboratory I/c is red colour

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mm, the test shall be repeated. If identical results follow, the CBR corresponding to 5 9 mm penetration shall be taken for design. PRECAUTIONS The contact between plunger and soil must be 100% with plunger moves perfectly vertical in order to avoid the error in load application. The proving ring selected generally higher capacity for dense soil. DATE OF SUBMISSION GRADE SIGNAURE OBSERVATIONS CBR TEST Density NMC Condition of specimen at undisturbed/remoulded/ Test : soaked/unsoaked Type of compaction : Static/Dynamic Compaction Light/Heavy Compaction Proving ring capacity Proving ring No. Proving ring load factor C Dial Gauge Constant Surcharge weight used Penetration Data DGR PRR Penetration mm =DGR x G Load kg= PRR x C

10

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Figure: Set up for CBR test

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