Concept explainers
(a)
Find the expected primary consolidation settlement.
(a)
Answer to Problem 11.6P
The expected primary consolidation settlement
Explanation of Solution
Given information:
The compression index
The thickness of the clay layer (H) is 4 m.
The average permanent load on the clay layer
The average effective overburden pressure
The initial void ratio
Calculation:
Determine the maximum primary consolidation settlement caused by the structural load
Substitute 0.5 for
Therefore, the expected primary consolidation settlement is
(b)
Find the pre-compression time.
(b)
Answer to Problem 11.6P
The pre-compression time
Explanation of Solution
Given information:
The average permanent load on the clay layer
The average effective overburden pressure
The surcharge load per unit area
The coefficient of consolidation
The thickness of the clay layer (H) is 4 m.
Calculation:
Determine the ratio of
Substitute
Determine the value of
Substitute
Refer Figure 11.6, “Plot of U against
For
The degree of consolidation is
Refer Figure 11-8, “Plot of mid plane degree of consolidation against
For
The time factor is
Determine the pre-compression time
Here,
Here, the drainage is two-way. Therefore,
Substitute 0.45 for
Thus, the pre-compression time is
(c)
Find the surcharge pressure that would eliminate the primary consolidation settlements beyond the preloading period.
(c)
Answer to Problem 11.6P
The surcharge pressure that would eliminate the primary consolidation settlements beyond the preloading period is
Explanation of Solution
Given information:
The coefficient of consolidation
The required time (t) is 6 months.
The thickness of the clay layer (H) is 4 m.
The average permanent load on the clay layer
The average effective overburden pressure
Calculation:
Determine the time factor using the formula:
Substitute 6 months for
Refer Figure 11-8, “Plot of mid plane degree of consolidation against
For
The value is
Determine the value of
Substitute
Determine the surcharge pressure using the formula:
Substitute 0.625 for
Simplify the Equation.
Thus, the surcharge pressure that would eliminate the primary consolidation settlements beyond the preloading period is
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Chapter 11 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
- 11.12 A 2-m clay layer in the field has a current effective stress, o= 70 kN/m. There is a net stress increase, Ao = 180 kN/m², due to a foundation load. Calculate the expected primary consolidation settlement. The results of a consolidation test on the clay are given below. o' (kN/m?) e 0.98 12 0.94 50 0.82 200 0.73 400 © Cengage Leaming 2014arrow_forward13. Situation 13 - The soil is acted upon by a uniformly distributed load ΔP = 60 kPa at the ground surface. a. Compute the settlement of the clay layer, in mm, caused by primary consolidation if the preconsolidation pressure of clay is 230 kPa. Use Cs = Cc/5. Round off to the nearest whole number. b. Compute the settlement of the clay layer, in mm, caused by primary consolidation if the clay is normally consolidated. Round off to the nearest whole number. c. Compute the settlement of the clay layer, in mm, caused by primary consolidation if the preconsolidation pressure of clay is 200 kPa. Use Cs = Cc/5. Round off to the nearest whole number.arrow_forwardKINDLY GET THE REAL ANSWER WITH EXPLAIN STEP Given that B =1 m, L = 3 m, and Q = 110 kN, the soil characteristics given in the figure are Cs = 1/5 Cc, Ꝺ’c= 40 kN/m2. Field monitoring indicated that the foundation settlement was 19 mm during the first 12 months. Estimate the average stress increase in the clay layer due to the applied load. Estimate the primary consolidation settlement. What is the degree of consolidation after 12 months? Estimate the coefficient of consolidation for the pressure range. Estimate the settlement in 24 months.arrow_forward
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