9. A consolidated drained test was carried out on a sandy clay under a cell pressure of 250 kPa. A constant back pressure of 120 kPa applied throughout the test. The dimensions of the sample were 76 mm x 38 mm. Addional test data recorded at failure were: Load transducer force = 368 N Measured change in volume = 2.42 x 10-6 m³ Axial deformation = 2.05 mm Determine the major principal stress, o, at failure.

9. A consolidated drained test was carried out on a sandy clay under a cell pressure of 250 kPa. A constant back pressure of 120 kPa applied throughout the test. The dimensions of the sample were 76 mm x 38 mm. Addional test data recorded at failure were: Load transducer force = 368 N Measured change in volume = 2.42 x 10-6 m³ Axial deformation = 2.05 mm Determine the major principal stress, o, at failure.

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter10: Shear Strength Of Soil

Section: Chapter Questions

Problem 10.12P

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d) An oedometer test was also performed on a (saturated) reconstituted sample obtained at the site. The initial void ratio was calculated as 1.005 and the initial sample height was 20 mm. The following measurements were reported for each of the 24-hr stress increments: Table 4. Oedometer test measurements Normal stress (kPa) 1.5 13 26 52 104 208 416 Change in sample height (mm) 0.419 0.199 0.229 0.209 0.208 0.199 Plot the evolution of the void ratio resulting from the data above using semi-logarithmic axes (i.e. produce an e-log o'y plot). Is there anything you can comment on the stress history and consolidation state of the soil?
3. In a drained tri-axial test, a specimen is confined under pressure and axially loaded until failure. The failure conditions of the specimen are analyzed for shear strength. What is the value of the minor principle stress? Half the value of the major principle stress Twice the value of the major principle stress . The same as the confining pressure The same as the cohesion value ● ● ●
A CID TXC test was performed on a sample of sand. At the end of consolidation, the back pressure was 140 kPa, and the cell pressure was 340 kPa. At failure, the deviator stress was (ơ1 – 03)f = 200 kPa. a. What was the total pore water pressure, u, at failure? b. Calculate the principle effective stresses, ơi' and os', at failure. c. Calculate the friction angle, d', for this soil.
A series of drained tri-axial tests were carrierd aut on a specimens of a sand prepared at the same porosity and the following results wer obtained at failure All Around Pressure, kPa 50 100 Principal Stress Difference, kPa 180 285 Calculate the value of the angle of shearing resistance What is the value of coliesion, Pa The maximum principal stress in kPa for a chamber pressure of 135 kPa
5. Triaxial tests were conducted on undisturbed samples of clay under CU conditions. Data from the test are summarized in the Table 2. Graph the Mohr's circles and draw in the failure envelope. Determine the strength parameters c' and ("? Table 2. Data from CU Tests Cell pressure (3 (kPa) 359 719 719 Test A B C Pore pressure at Failure u (kPa) 339 585 451 Deviator Stress at Failure. (1-(3 (kPa) 539 731 1015
Can TRIAXIAL TESTS be performed on sand samples? Briefly explain. The results of an undrained triaxial test on a clay soil sample are given in table below Cell Pressure (kN/m2) 200 400 600 Additional Axial Load at Failure (N) 342 388 465 Each sample, originally 76mm long and 38mm in diameter, experienced a vertical deformation of 5.1mm. Evaluate the stress at failure for each cell pressure given in table above. Draw Mohr Circles and determine the shear strength parameters of the soil.
A triaxial compression test was conducted on a saturated soil sample to determine its shear strength parameters: effective cohesion (C') and effective friction angle (O'). The confining pressure used during the test was 30 psi. The deviator stress on the sample at the time of failure was 40 psi. The porewater pressure measured at the time of failure was 5 psi a) The figure below shows the stress conditions on the sample at the time of failure. Provide the values of total stresses, o1 and oz on the sample. Total horizontal stress, o3 (psi) = (Report to the nearest whole number, i.e. no decimals) Total vertical stress, o1 (psi) (Report to the nearest whole number, i.e. no decimals) %3D b) The figure below shows the effective stress Mohr's Circle for the above soil sample at failure. What are the values of effective normal stresses at points A and B?
Two undrained triaxial tests were conducted on soil specimen, and they gave the following results: Sample Confining Pressure Deviator Stress A 350 kN/m² B 500 kN/m² 150 kN/m² 300 kN/m² The shear strength of sample A in the plane of it's normal stress is A 588 kPa B 283 kPa C 730 kPa D 165 kPa Correct Option
c. An undisturbed soil sample, 110 mm in diameter and 220 mm in height, was tested in a triaxial machine. The sample sheared under an additional axial load of 3.35 kN with a vertical deformation of 21 mm. The failure plane was inclined at 50° to the horizontal and the cell pressure was 300 kN/m². i. Draw the Mohr circle diagram representing the above stress conditions, and from it determine: - Coulomb's equation for the shear strength of the soil, in terms of total stress; - the magnitude and obliquity of the resultant stress on the failure plane. ii. A further undisturbed sample of the soil was tested in a shear box under the same drainage conditions as used for the previous test. If the area of the box was 3600 mm² and the normal load was 500 N, what would you expect the failure stress to have been?
An undisturbed soil sample, 110 mm in diameter and 220 mm in height, was tested in atriaxial machine. The sample sheared under an additional axial load of 3.35 kN with avertical deformation of 21 mm. The failure plane was inclined at 50˚ to the horizontal and the cell pressure was 300 kN/m2. i. Draw the Mohr circle diagram representing the above stress conditions, and from it determine:− Coulomb’s equation for the shear strength of the soil, in terms of total stress;− the magnitude and obliquity of the resultant stress on the failure plane.
4- In a consolidated-drained triaxial test on a clay, the specimen failed at a deviator stress of 2,590 lb/ft². If the effective stress friction angle is known to be 29°, what was the effective confining pressure at failure?
The results obtained from a series of CU test on a soil gave the following results : CCU = C'CU = 0 cu 15°; 'cu = 30° CU A sample of this soil was tested in a CU test under a cell pressure of 150 kN/m². Determine (i) deviator stress at failure (ii) pore water pressure at failure (iii) minor principal effective stress at failure (iv) major principal effective stress at failure (v) the magnitude of Skempton's pore water pressure parameter(at failure) A