Question

A 3.0 m thick singly drained normally consolidated clay layer has eo 5 0.89, Cc 5 0.46, and cv 5 3.5 m2 /year. The effective overburden pressure at the middle of the layer is 105.0 kN/m2 . It is proposed to build a large warehouse that is expected to impose a pressure of 50.0 kN/m2 at the ground level.

a. What would the primary consolidation settlement be?
b. If the engineer proposes to preload the site with a pressure of 90.0 kN/m^2, how long should this surcharge be left to ensure there is no postconstruction settlement when the warehouse is built?

Answer 1

= 0.9 years ≈ 1 year

Step-by-step explanation:

A) Determine the primary consolidation settlement

attached below is the detailed solution

primary consolidation = 358.77 mm

B) first calculate the degree of consolidation

looking at the attached graph at u = 46% , Tv = 0.35

using the formula ; Tv = ( Cv*T ) / H^2

where ; Cv = 3.5m^2

Tv = 0.35

H = 3 m ( single drained )

hence T = ( Tv * H^2 ) / Cv

= ( 0.35 * 9 ) / 3.5

= 0.9 years ≈ 1 year

attached below is the remaining part of the solution