A CU triaxial test was carried out on a silty clay that was isotopically consolidated using a cell pressure of 125 kPa. The following data were obtained: Axial load (kPa) 0 5.5 11.0 24.5 28.5 35.0 50.5 85.0 105.0 120.8 Axial strain, &₁ (%) 0 0.05 0.12 0.29 0.38 0.56 1.08 2.43 4.02 9.15 Au (kPa) 0 4.0 8.6 19.1 29.3 34.8 41.0 49.7 55.8 59.0 (a) Plot the deviatoric stress vs. axial strain and excess porewater pressure vs. axial strain, respectively. (b) Determine the undrained shear strength (sµ). (Note: we assume that the sample reaches failure). (c) Determine the total principal stresses (0₁,03) and the effective principal stresses (0₁, 03') at the failure, respectively.

A CU triaxial test was carried out on a silty clay that was isotopically consolidated using a cell pressure of 125 kPa. The following data were obtained: Axial load (kPa) 0 5.5 11.0 24.5 28.5 35.0 50.5 85.0 105.0 120.8 Axial strain, &₁ (%) 0 0.05 0.12 0.29 0.38 0.56 1.08 2.43 4.02 9.15 Au (kPa) 0 4.0 8.6 19.1 29.3 34.8 41.0 49.7 55.8 59.0 (a) Plot the deviatoric stress vs. axial strain and excess porewater pressure vs. axial strain, respectively. (b) Determine the undrained shear strength (sµ). (Note: we assume that the sample reaches failure). (c) Determine the total principal stresses (0₁,03) and the effective principal stresses (0₁, 03') at the failure, respectively.

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter12: Shear Strength Of Soil

Section: Chapter Questions

Problem 12.18P

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A CU triaxial test was carried out on a silty clay that was isotopically consolidated using a cell pressure of 125 kPa. The following data were obtained: Axial load (kPa) 0 5.5 11.0 24.5 28.5 35.0 50.5 85.0 105.0 120.8 Axial strain, E₁ (%) 0 0.05 0.12 0.29 0.38 0.56 1.08 2.43 4.02 9.15 Au (kPa) 0 4.0 8.6 19.1 29.3 34.8 41.0 49.7 55.8 59.0 (a) Plot the deviatoric stress vs. axial strain and excess porewater pressure vs. axial strain, respectively. (b) Determine the undrained shear strength (su). (Note: we assume that the sample reaches failure). (c) Determine the total principal stresses (0₁,03) and the effective principal stresses (0₁, 03') at the failure, respectively.
1. Triaxial compression tests are done on quartzite rocks, the results are shown below. (0₁+03)/2 -964.25 14500 19575 23200 29000 43210 63075 psi (01-03)/2 964.25 14500 18850 21750 26100 35960 48575 psi Comment on the applicability of each of the Mohr-Coulomb, Griffith, and Hoek-Brown criteria for the testing results.
2. A series of consolidated, undrained triaxial tests were carried out on specimens of a saturated clay under no backpressure. The test data at failure are summarized: Confining Pressure (kPa) Deviator Stress (kPa) Pore Water Pressure (kPa) 150 192 80 300 341 154 450 504 222 a. Draw the Mohr circles and find the cohesion and friction angles in terms of effective stresses. b. Compute Skempton’s A-parameter at failure for all three specimens. c. Is the soil normally consolidated or overconsolidated? Why? d. Another specimen of the same clay that was consolidated under a cell pressure of 250 kPa was subjected to a consolidated, drained triaxial test. What would be the deviator stress at failure?
A triaxial shear test was performed on a well-drained sand sample. The normal stress on the failure plane and the shear stress on the failure plane, at failure were determined to be 6100 psf and 4600 psf, respectively. a. Determine the angle of internal friction of the sand? b. Determine the angle of the failure plane? c. Determine the maximum principal stress? Please answer this asap. For upvote. Thank you very much
5. A consolidated, undrained triaxial test is being carried out on a normally consolidated clay where c - 0 and p'= 26'. The triaxial specimen was consolidated under a cell pressure of 300 kPa and backpressure of 80 kPa. Skempton's A parameter at failure is estimated to be 0.80. The drainage valve has since been dosed and the vertical deviator stress increased to failure. What would be the deviator stress and pore water pressure at failure?
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.
Three specimnens of clay having a small air-void content were tested in the shear box. Shear loading was started immediately after the application of the normal load and was completed in 8 minutes. The results are as follows: Normal Stress (kN/m2) Shear stress at failure (kN/m2) O Find the apparent cohesion of the clay. Find the angle of shearing resistance of the clay. What value of c would be obtained from an unconfined compression test on 145 241 337 103 117 131 the same soil?
Two drained triaxial tests were performed on a saturated overconsolidated clay and the results are shown below. Determine the effective and total shear strength parameters. Specimen I: Specimen II: 0²-70 kPa a=160 kPa Od 130 kPa Od-223.5 kPa
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.
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?
Question 3 The results of two consolidated-drained test triaxial tests on a clay are given below: Specimen No. Chamber Pressure Deviator Stress 220 400 105 II 210 1. Determine the angle of internal friction. 2. Determine the cohesion of the clay. 3. Determine the normal stress on the point on the failure plane of the 2"d specimen. O Question 1: A. 26.744 O Question 1: B. 26.042 O Question 1: C. 27.871 O Question 1: D. 27.486 O Question 2: A. 10.737 O Question 2: B. 12.141 O Question 2: C. 17.372 O Question 2: D. 14.836 O Question 3: A. 317.694 O Question 3: B. 232.575 O Question 3: C. 230.306 O Question 3: D. 322.194 O O O O O O O CO
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 mm? and the normal load was 500 N, what would you expect the failure stress to have been?