Question

(Figure I) 2. For the problem illustrated in Figure 1, determine the depth of tension crack for the following conditions. a) Wall does not move with respect to the backfill. b) At the moment of shear failure initiation in the backfill when the wall moves away from the soil. c) At the moment of initiation of shear failure when the wall is pushed to move into the backfill q-10 kPa Ysat = 20 kN / m? 2 m yat-18 kN/m 30, c'-0kPa Figure I) 2. For the problem illustrated in Figure 1, determine the depth of tension crack for the following conditions a) Wall does not move with respect to the backfill. b) At the moment of shear failure initiation in the backfill when the wall moves away from the soil. c) At the moment of initiation of shear failure when the wall is pushed to move into the backfill.

Answer 1

(1) As the soil is cohesive the height that is as follows: K 1-sinø = 1-sin 25 K, = 0.577 Oy 10(20-9.81)h P, K,o,-2cK P 0.577(10+(20-9.81)/)-2x12/0.577 We are not taking second portion of the soil because here the soil is cohesionless so, tension crack will not occur To find the depth of tension crack equate this equal to zero. 0 0.577(10+(20-9.81)h)-2x12vVo.577 h=2.12 m (2) Wall moves away from the soil, so this is active pressure case 1-sin k, 1+ sin 1-sin 25° 1sin 25 k = 0.405 P 0.405 (10+(20-9.81)h)-2x12/0.405 0 0.405 (10+(20-9.81)/)-2x12/0.405 h=2.71 m (3) Wall moves toward the soil, so this is passive pressure case

1+sin k 1-sin 1 sin 25 1 sin 25 k 2.47 p P 2.47 (10+(20-9.81)h)-2x12/2.47 0 2.47 (10+(20-9.81)h)-2x12/2.47 h 0.51 m