N B 0 A Horizontal The stresses shown in the figure are applied at a point in a dry clayey sand soil mass. A= 50 kPa and B= 125 kPa The shear strength parameters of the clayey sand are: c'= 9kPa and p'=29° 0=30° a) The value of the shear stress, T, is slowly increased. What value would cause shear failure at this point (in kPa)? b) At failure, what angle does the failure plane make with the horizontal (in degrees)?

N B 0 A Horizontal The stresses shown in the figure are applied at a point in a dry clayey sand soil mass. A= 50 kPa and B= 125 kPa The shear strength parameters of the clayey sand are: c'= 9kPa and p'=29° 0=30° a) The value of the shear stress, T, is slowly increased. What value would cause shear failure at this point (in kPa)? b) At failure, what angle does the failure plane make with the horizontal (in degrees)?

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter8: Stresses In A Soil Mass

Section: Chapter Questions

Problem 8.25P: Refer to Figure 8.27. The flexible area is uniformly loaded. Given: q = 300 kN/m2. Determine the...

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2. The state plane stress in a mass of dense cohesionless sand (c=0) is described by the following stresses: Normal stress on horizontal plane = 100 kPa Normal stress on vertical plane = 50 kPa Shear stress on horizontal and vertical planes = ± 30 kPa Determine by means of the Mohr circle the magnitude and direction of the principal stresses. Is this state of stress safe against failure assuming φ= 30o?
10-14. The state plane stress in a mass of dense cohesionless sand is described by the following stresses: Normal stress on horizontal plane Normal stress on vertical plane = 200 kPa Shear stress on horizontal and vertical planes 370 kPa 80 kPa %3! Determine by means of the Mohr circle the magnitude and direc- tion of the principal stresses. Is this state of stress safe against failure? (After A. Casagrande.)
1. The following figure shows the stress-displacement results of four direct shear tests under different vertical stresses. 70 60 o'v=10 psi 50 - o'v=20 psi 40 Δσ'ν-40 psi o'v=80 psi 30 20 10 0.05 0.1 0.15 0.2 0.25 0.3 shear displ. [in] Based on the results above, develop the Mohr-Coulomb failure envelope. Indicate the cohesion (c') and calculate the drained friction angle (o'). shear stress [psi]
3 1. (a) An element of soil is subjected to the two-dimensional stresses shown in Figure Q1. 0, = 150 =-30 = 30 60° o, = 75 (All in kPa) Figure Q1 (1) Determine the normal and shear stresses on the P and Q planes which are orthogonal (ii) Determine the magnitudes and directions of the major and minor principal stresse (b) An undrained direct shear test with a hanger mass of 32 kg was performed on a sample of saturated clay. The plan dimensions of the shear box were 60 x 60 mm. The undrained shear strength of the clay is known to be Cu = 60 kPa. The critical state friction angle of the clay is known to be d'ern = 22°. What pore water pressure (u) in kPa, would the sample experience at the ultimate state? (c) Given that the pore pressure calculated from part (b) was negative, explain what this implies about the volume change that would have occurred to the sample (dilative or contractive) if the test was done under drained conditions.
SITUATION 5: A sand sample is subjected to direct shear testing at it's (in - situ) water content. Two tests are performed. For one of the tests, the sample shears at a stress of 400 kPa when the normal stress is 600 kPa. From these data, 15. Determine the value of the apparent cohesion. c. 230 kPa d. 221 kPa а. 100 kPa b. 179 КРа 16. Determine the corresponding angle of internal friction. a. 22.65 degrees b. 26.57 degrees c. 32.54 degrees d. 18.43 degrees
Refer to Figure 10.42. Due to application of line loads q1 and q2, the vertical stress increase at point A is 58 kN/m2. Determine the magnitude of q2. Figure 10.42
Use Eq. (6.14) to determine the stress increase () at z = 10 ft below the center of the area described in Problem 6.5. 6.5 Refer to Figure 6.6, which shows a flexible rectangular area. Given: B1 = 4 ft, B2 = 6 ft, L1, = 8 ft, and L2 = 10 ft. If the area is subjected to a uniform load of 3000 lb/ft2, determine the stress increase at a depth of 10 ft located immediately below point O. Figure 6.6 Stress below any point of a loaded flexible rectangular area
EB and FG are two planes inside a soil element ABCD as shown in Figure 10.50. Stress conditions on the two planes are Plane EB: EB = 25 kN/m2; EB = +10 kN/m2 Plane FG: FG = 10 kN/m2; FG = 5 kN/m2 (Note: Mohrs circle sign conventions for stresses are used above) Given ; = 25, determine: a. The maximum and minimum principal stresses b. The angle between the planes EB and FG c. The external stresses on planes AB and BC that would cause the above internal stresses on planes EB and FG
Refer to Figure 8.27. The flexible area is uniformly loaded. Given: q = 300 kN/m2. Determine the vertical stress increase at point A located at depth 3 m below point A (shown in the plan). FIG. 8.27
Ex 20 The shear strength parameters of N.C.C. are; =15, B = 30' a) In a Cutest on the same soil, the confining pressure is (150) kulu². Find the deviator stress at failure. b) In a slow direct shear test, the normal stress is (100) kN/m². Find the shear stress at failure. c) In an Unconfined compression test, the unconfined shear strength (Cu) is (50) kN/m². Find the pore water pressure at failure (assume c =o).
The soil profile shown consists of dry sand (4-m thick) which overlies a layer of clay (3-m thick). Ground water table is located at the interface of the sand and clay. a. If the water table rises to the top of the ground surface, what is the change in the effective stress (in kPa) at the bottom of the clay layer? Round off to two decimal places. (ANSWER: 26.336) b. Compute the effective stress at the bottom of the clay layer in kPa. Round off to three decimal places (ANSWER: 97.686) c. How many meters must the ground water table rise to decrease the effective stress by 14 kPa, at the bottom of the clay layer? Round off to two decimal places (ANSWER: 2.13)
The vertical and horizontal stresses at a certain point in soil are as follows:σx = 50 kPaσx = 100 kPaτzx = - 20 kPa a) Determine magnitudes and directions of the major and minor principal stresses.b) Determine magnitude and direction of maximum shear stress.c) Determine the normal and shear stresses acting on a soil element inclined at 60 clockwise from the horizontal plane.