Question

For a foundation, find the elapsed time in which 90% of ultimate settlement will occur.  The coefficient of consolidation is 4*10^-4cm^2/s. The average drainage path is 50cm.

(a) 56.38 days

(b) 43.78 days

(c) 61.34 days

(d) 78.23 days

This question was posed to me in class test.

This interesting question is from Consolidation Problems topic in chapter One Dimensional Consolidation of Geotechnical Engineering I

Answer 1

Correct choice is (c) 61.34 days

The explanation: Given,

d=50 cm

Cv=4×10-4 cm^2/s

For consolidation of 90%, U>60%

Therefore Tv= 1.7813 – 0.9332 log10 (100-U)

Tv= 1.7813 – 0.9332 log10 (100-90)

Tv= 0.848

\(G_0 = \frac{(T_v)_{90}d^2}{C_v} = \frac{0.848×(50)^2}{4×10^{-4}}s\)

G0= 61.34 days.