An unconfined compression (UC) test was conducted on a 50-mm-diameter and 100-mm-high cylindrical sample of silty clay (Gs=2.70). The total mass of the soil sample was 402.52 g. The sample, which was assumed to be fully saturated at the time of the test, failed at an axial load of 318 N at an axial displacement of 7.15 mm. (a) Calculate the total axial stress at failure. (b) Calculate the undrained shear strength of the sample. (c) If it is previously known that the angle of friction is equal to 22° for the silty clay, estimate the effective horizontal stress and pore-wate) pressure at failure. (d) Post-test gravimetric water content of the sample (w) was found to be 19.3%. Does this measured value of w affect the interpretation of your test results? If it does, in what way(s) and why?

An unconfined compression (UC) test was conducted on a 50-mm-diameter and 100-mm-high cylindrical sample of silty clay (Gs=2.70). The total mass of the soil sample was 402.52 g. The sample, which was assumed to be fully saturated at the time of the test, failed at an axial load of 318 N at an axial displacement of 7.15 mm. (a) Calculate the total axial stress at failure. (b) Calculate the undrained shear strength of the sample. (c) If it is previously known that the angle of friction is equal to 22° for the silty clay, estimate the effective horizontal stress and pore-wate) pressure at failure. (d) Post-test gravimetric water content of the sample (w) was found to be 19.3%. Does this measured value of w affect the interpretation of your test results? If it does, in what way(s) and why?

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

See similar textbooks

Similar questions

A sample of soil is subjected to direct shear testing at its normal water content. Two test are performed. For one of the test, the sample fails at a shear stress of 144 KN/m2 when the normal stress is 192 KN/m2. In the second test, the sample shears at a stress of 168 KN/m2 when the normal stress is 239.4 KN/m2. From these data, Calculate the following:a) Angle of internal frictionb) Cohesion of soilc) Shearing resistance of the soil at a depth of 3600 mm if it has a unit weight of 16.4 KN/m3.
A consolidated-undrained triaxial compression test was performed on a normalconsolidated clay sample. During the experiment, the confining pressure was 140 kPa, thedeviator stress was 125 kPa, and the pore water pressure was 75 kPa at the time of failure.According to the information given:i- Find the consolidated-undrained internal friction angle of the clay. ii- Find the drained friction angle of the clay
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
: In a tri-axial test of a silty soil, the sample failed at normal stress of 475 kPa and a shear stress of 350 kPa. Which of the following gives the angle of internal friction? Compute the angle that the failure plane makes with the x-axis. Compute the maximum failure stress.
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.
An undisturbed soil sample, 100 mm in diameter and 200 mm high, was tested in a triaxial machine. The sample failed at an additional axial load of 3 kN with a vertical deformation of 20 mm. The failure plane was inclined at 50° to the horizontal and the cell pressure was 300 kN/m2, Determine, from Mohr’s circle, the cohesion in kPa. a.117.8 b.91.3 c.125.6 d.87.2
In a tri-axial test of silty soil, the sample failed at normal stresses of 521 kPa and a shear stress of 200 kPa. Compute the maximum failure stress. a. 781 kPa b. 510 kPa c. 838 kPa d. 812 kPa
In a tri-axial test of normally consolidated clay, the sample subjected to chamber confining pressure of 250 kPa and failed when deviator stress is 350 kPa. Which of the following gives the angle of internal friction? Which of the following gives the shear stress at failure? Which of the following gives the effective normal stress at maximum shear?
A dry cohesionless soil is tested in a triaxial test to determine the angle of internal friction f. A confining pressure equal to 1,000 psf is used. The sample fails when the axial load causes a stress of 3,200 psf. What is the value of f?
A tri-axial compression test on a cohesive sample of cylindrical in shape, which fails along a plane making an angle of 60 degrees with the horizontal, yields the following effective stress. Compute the angle of internal friction. Compute the cohesion of the soil sample. Compute the shear stress (MN/m^2) at the rupture plane.
A dry sand sample in a triaxial test failed when the confining stress (minor principal stress) was 1,000 psf and the axial stress (major principal stress) was 4,000 psf. What is the angle of internal friction for this soil?
The size of a sand specimen in a direct shear test was 50 mm x 50 mm x 30 mm (height). It is known that, for the sand, tan phi prime = 0.65/e (where e = void ratio) and the specific gravity of soil solids Gs = 2.65. During the test, a normal stress of 140 kN/m^2 was applied. Failure occured at a shear stress of 105 kN/m^2. What was the mass of the sand specimen?