The lower sand layer in the soil profile shown below is in an artesian condition. Calculate: 2 a) The effective stress () at the top and base of the clay layer. b) The height of water in the piezometer for = 0 at the base of the clay layer. > c) The maximum depth (Z) of the proposed excavation (Figure Q1 (b)). (Assume Z>2 m).

The lower sand layer in the soil profile shown below is in an artesian condition. Calculate: 2 a) The effective stress () at the top and base of the clay layer. b) The height of water in the piezometer for = 0 at the base of the clay layer. > c) The maximum depth (Z) of the proposed excavation (Figure Q1 (b)). (Assume Z>2 m).

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter7: Permeability

Section: Chapter Questions

Problem 7.20P

See similar textbooks

Similar questions

An embankment consists of clay fill for which c=25 kPa and angle of internal friction is 260 9from consolidated undrained test with pore pressure measurement) The weight of fill per unit volume is 18.64 kN/m3. Compute the stress in kPa at depth of 20 m. a. 192.8 b. 62.5 c. 21.6 d. 372.8
An embankment consists of clay fill for which c=25 kPa and angle of internal friction is 260 9from consolidated undrained test with pore pressure measurement) The weight of fill per unit volume is 18.64 kN/m3. Compute the stress in kPa at depth of 20 m. Show free body diagram a.21.6 b.372.8 c.192.8 d.62.5
Soil Mechanics An embankment consists of clay fill for which c′ = 25 kN/m2 and φ = 27° (from consolidated undrained tests with pore-pressure measurement). The average bulk unit-weight of the fill is 2 Mg/m3. Estimate the shear-strength in kPa of the material on a horizontal plane at a point 20 m below the surface of the embankment, if the pore pressure at this point is 180 kN/m2 as shown by a piezometer. a. 133 b. 100 c. 166 d. 200
44.) A 5 m-thick clay (Gs = 2.65, water content = 0.28) is overlain by a 4.50m-thick layer of sand (Gs = 2.60, e = 0.70, S = 0.85). The ground water table is located 4.50 m from the ground surface. Compute for the following: 1. At what depth would the vertical effective stress be equal to 120 kPa? 2. What is the vertical effective stress at a depth 9 m below the ground surface? 3. The depth of excavation required to reduce the effective stress at the bottom of the clay layer by 100 kPa. Question 1: A. 1.94 Question 1: B. 3.99 Question 1: C. 6.44 Question 1: D. 8.49 Question 2: A. 168.9 Question 2: B. 44.1 Question 2: C. 120.1 Question 2: D. 124.8 Question 3: A. 1.83 Question 3: B. 7.67 Question 3: C. 3.17 Question 3: D. 6.33
A 5m thick clay (Gs = 2.65, water content = 0.28) is overlain by a 4.5m thick layer of sand (Gs = 2.60, e = 0.70, S = 0.85). The ground water table is locate 4.5m from the ground surface. 1. at what depth would the vertical effective stress be equal to 120kpa?2. what is the vertical effective stress at a depth 9m below the ground surface? 3. what depth of excavation required to reduce the effective stress at the bottom of the clay layer by 100kpa?
A 5 m-thick clay (Gs = 2.65, water content = 0.28) is overlain by a 4.50m-thick layer of sand (Gs = 2.60, e = 0.70, S = 0.85). The ground water table is located 4.50 m from the ground surface. Compute for the following: 1. At what depth would the vertical effective stress be equal to 120 kPa? 2. What is the vertical effective stress at a depth 9 m below the ground surface? 3. The depth of excavation required to reduce the effective stress at the bottom of the clay layer by 100 kPa.
A soil profi le consists of a clay layer underlain by a sandlayer, as shown in Figure P7.17. If a tube is inserted intothe bottom sand layer and the water level rises to 1 mabove the ground surface, determine the vertical effective stresses and porewater pressures at A, B, and C. IfKo is 0.5, determine the lateral effective and lateral totalstresses at A, B, and C. What is the value of the porewater pressure at A to cause the vertical effective stressthere to be zero?
A soil profile is shown in Figure Q3(b)(i). The groundwater level is located on the ground surface. The sand layer is under artesian pressure where the excess pore water pressure is 40 kN/m^2. (i) Calculate the total vertical stress, pore water pressure and effective vertical stress at the base of each layer. (ii)Determine the increment of the effective stress at the base of sand layer if the 1.5m height fill will be imposed on the ground surface. Note that, the density of the fill material is 1750 kg/m^3. (iii) The excavation will be made in the clay layer for the basement construction. Evaluate the stability of the soil from boiling or quick condition. The depth of the excavation is shown in Figure Q3(b)(ii). (iv)Propose the maximum depth of cut that can be made to avoid boiling or quick condition.
Determine the stress increase due to the embankment load at point A as shown in Figure 2. The unit weight of the embankment fill is 115pcf
A 8 m-thick layer of stiff saturated clay is underlain by a layer of snad (Figure Q3). The sand is under artesian pressure. (water pressure head in the sand layer is shown on the piezometer). Calculate the maximum depth of cut, H, that can be made in the clay.
A soil profile, under surcharge load of 25 kN/m2 at ground level, consists of 6m sand and 3m clay layer. Ground water table is 2m below sand layer. Dry unit weight and saturated unit weight of sand is 15.80kN/m3 and 16.90kN/m3 respectively. Clay layer, Gs=2.67 and saturated unit weight is 18.80 kN/m3. Determine a)Increase in stress at the mid layer of clay b) With dewatering 2m, what is the stress increase at the mid layer of clay c) How much must the water level be lowered to me more effective than the surcharged load?
A soil profile is shown in Figure 7.28. An embankment load of 500 kg/cm² is placed on the ground surface. Define the following: a. How much water will rise in the pizometer immediately after applying the load. b. What is the degree of consolidation at A if h = 26 ft. c. Determine the magnitude of h if the degree of consolidation at point A is 50%. And Draw the curve NB: part A Assume that the increase in pore water pressure is uniform over the entire depth of very clayey having a thickness of 10 ft.