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Concept explainers
Find the consolidation settlement of the group.
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Answer to Problem 18.25P
The consolidation settlement of the group is
Explanation of Solution
Given information:
The total load
The length
The length
The length
The unit weight
The saturated unit weight
The initial void ratio
The coefficient of consolidation
The saturated unit weight
The initial void ratio
The coefficient of consolidation
The saturated unit weight
The initial void ratio
The coefficient of consolidation
The saturated unit weight
The initial void ratio
The coefficient of consolidation
Calculation:
Show the pressure diagram as in Figure 1.
Determine the total length L of pile using the formula.
Substitute 3 m for
The load starts transmitting to the soil at the pile depth of
Determine the depth at which the load on the group pile
Here, L is the depth of normally consolidated clay layer 1.
Substitute 10 m for L.
Thus, the settlement starts in NCC layer 1.
Determine the stress
Here,
Take the unit weight of water as
Substitute
Determine the stress
Here,
Substitute
Determine the stress
Here,
Substitute
Calculate the stress
Here,
Substitute 2,500 kN for
Calculate the stress
Substitute 2,500 kN for
Calculate the stress
Substitute 2,500 kN for
Determine the value of
Substitute
Determine the value of
Substitute
Determine the value of
Substitute
Determine the consolidated settlement
Here,
Substitute 0.30 for
Determine the consolidated settlement
Here,
Substitute 0.35 for
Determine the consolidated settlement
Here,
Substitute 0.26 for
Determine the total
Substitute 0.186 m for
Therefore, the consolidated settlement of the group pile is
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Chapter 18 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
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- A frictional pile with a circular cross-section (diameter D) is pushed into the soil to a distance (L) and then it is subjected to an axial force (P) on its top end. Derive a formula to calculate the normal stress in any section x. P fN, D Cross sectionarrow_forward8. Plot the consolidation curve for the data given below and determine the preconsolidation stress (o'c). Note: tsf = tons per square foot. tsf e 0.25 0.93 0.5 0.92 0.9 2 0.88 4 0.84 1 8 0.75 16 0.59 32 0.38 4 0.43 1 0.48 9. For the plot in problem 8, determine Cr and Cc.arrow_forwardduring derivation of Terzaghi's conventional 6-3 What is an overconsolidated clay and what causes the overconsolidation? Give theory of consolidation. What is an overconsolidated clay and what causes the overconsolidation? Give three possible causes. Why moy lowearrow_forward
- A frictional pile with a circular cross- section (diameter = D) is pushed into the soil to a distance (L) and then it is subjected to an axial force (P) on its top end. Derive a formula to calculate the normal stress in any section x. f N/mm2 Cross sectionarrow_forwardDetermine the primary consolidation settlement for the 20 m long pile group shown below. Soil properties by layer are given in the figure, and the clay layers are normally consolidated. Assume a 2:1 load spread starting at a depth of 2/3 of the embedment depth, L. The pile group is square and has dimensions 2.6 m by 2.6 m in plan view. The groundwater table is 1 m below the ground surface. = 4000 kN 1 m Sandy soil Y =18.5 kN/m³ Q'=330 V W.T. 7 m -Group.. piles Clay 1 Y =17.2 kN/m3 e=0.83 C= 0.23 L= 20 m Ax B = 2.6 m x 14 m 2.6 m Clay 2 Y =17.5 kN/m3 e,=0.78 C=0.22. 8 m Clay 3 Y =18.0 kN/m? eo=0.76 C=0.20 12 m Rockarrow_forwardIn clay, pile cap and settlement of a pile grouparrow_forward
- A 50 cm square precast pile is driven by 9 m into a sandy soil. The standard penetration test results, prformed on this ground, are given in the table below: Depth below ground surface (m) SPT (Nss) 1.5 3.0 4.5 4 6 6.0 12 12 20 24 35 39 If the skin resistance is equal to {T, = 2 x (average Nss along the pile shaft)) kPa. Compute the factor of safety available, if 1100 kN of compressive load is applied on this pile. 7.5 9.0 10.5 12.0arrow_forwardWould the following separate, unrelated actions cause consolidation settlement in a clay layer? Answer Yes or No and describe why. A) Only adding a wide surface load of great pressure (e.g. embankment). B) Only drilling a vertical pipe throughout a clay layer. C) Only drawing down the water table by dewatering through the vertical pipe.arrow_forwardA 50 cm diameter precast pile is driven by 9 m into a sandy soil. The standard penetration test results, prformed on this ground, are given in the table below: Depth below ground surface (m) 3.0 4.5 6.0 7.5 9.0 10.5 12.0 SPT (N55) 6 12 12 20 24 35 39 1.5 4 If the skin resistance is equal to (ts=2 x (average Nss along the pile shaft)} kPa. Compute the number of piles that needed to support a total load of 4400 KN with factor of safety (2.5).arrow_forward
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