2. (10 points) A sample of sand is sheared in the following manner. First an all around normal st...
In a direct shear test on a sample of cohesionless sand, the vertical normal stress on the sample is 300 kPa and the horizontal shear stress at failure is 200 kPa. a) Assuming uniform stress distribution within the failure zone, determine the magnitude and direction of the principal stresses at failure. b) Explain if it is possible to determine the principal stresses in a direct shear sample for an applied horizontal shear stress which is not large enough to cause...
2. The results of a Consolidated Undrained (CU) triaxial test on a sand soil are in the figures below. The sample was subjected to a vertical load (do). At failure, the Δσ was 914 psi and the induced pore water pressure at failure (Au) was 683 psi. consolidated to a stress of 12 psi and then Au 6.83 psi σ,-12 psi -σ,-12 psi Sand At Failure Initial (Consolidation) A. Draw both the total and effective stress Mohr's Circles at failure...
The state of stress within the soil below the ground surface is σ.-28 kPa, σ,-14 kPa, and t-4 kPa on the horizontal plane. Using Mohr's circle; a) Find the magnitude and directions of the major and minor principal stresses, that is the plane on which there are no shear stresses. b) If the material is a loose sand with a known friction angle of p-30 degrees and c'-0, construct the Coulomb failure envelope and determine if this soil is in...
4. Shear Strength A sample of cohesive soil with undrained shear strength of 30 Kpa is beng tested in a triaxial est with a confining pressure of 15 Kpa (see the figure below). Sketch the failure envelope and Mohr's circle representing the state of stress at failure. Evaluate the following: (i) The vertical axial stress at failure. (ii) The major and minor principal stresses at failure (ii) The orientation of failure plane with respect to horizontal plane. (iv) The normal...
A drained direct shear box test was performed on a sample of saturated sand. The normal effective stress of 467 kPa was constant throughout the test, and the initial sample dimenstions were 60 mm x 60 mm in plan x 30 mm deep. In the vicinity of peak shear stress, the data recorded were: (20 points) Shear Stress, τ (kPa) 42.5 43.1 42.8 Relative horizontal displacement x (mm) 0.30 0.40 0.80 Upward movement of the shear box cap y (mm)...
Problems 39 ist four major factors that influence the internal friction angle of cohesionless soils 7-2 Define soil sensitivity and thixotropy In a direct shear test on a loose sand, a shearing stress of 36.1 kPa was recorded 7-3 while the normal stress on the failure plane was 66.4 kPa. (a) What are the shear strength parameters, c', φ'? (b) Find the major and minor principal stresses at failure. (c) Determine the shear strength at a normal stress of 110.0...
soil mechanics Q4:- A sand sample is tested in a direct shear device. The vertical normal stress on the sample is 300 kN/m². The horizontal shear stress at failure is equal to 210 kN/m². a. Compute the angle of internal friction for the sand and the magnitudes of the principal stresses at failure. b. During a consolidated drained triaxial test, a sample of the same sand failed at a principal stress difference of 130 kN/m². Determine the magnitudes of the...
(12 marks) (a) In a triaxial test for sand (c) the stress increment (s)-2.5o. What is the angle of internal frictica (o (b) A consolidated undrained (CU) triaxial test was performed on two samples of a clay and the results are: Test No. Cell pressure (kNm) Devilo stress ( km) Pore water pressure (kN) G; 1 150 500 220 (i) The Mohe circles and the failure line in terms effective stresses are drwn as shown in the figure below. List...
The following results were obtained from an undrained shear box test carried out on a set of undisturbed soil samples. 0.2 0.8 Normal Load (N) Strain (%) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 21 46 70 89 107 121 131 136 138 138 137 136 0.4 Shearing force (N) 0 33 72 110 139 164 180 192 201 210 217 224 230 234 237 236 0 45...
The following results were obtained from an undrained shear box test carried out on a set of undisturbed soil samples. 0.2 0.8 Normal Load (N) Strain (%) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 21 46 70 89 107 121 131 136 138 138 137 136 0.4 Shearing force (N) 0 33 72 110 139 164 180 192 201 210 217 224 230 234 237 236 0 45...