Question

A clay sample 24mm thick takes 20 minutes to consolidate 50% with single drainage. The field clay layer from which sample was obtained takes 386 days to consolidate 50% with single drainage. Find the depth of the clay layer in the field.

(a) 200cm

(b) 367cm

(c) 400cm

(d) 569cm

I have been asked this question in class test.

My doubt is from Consolidation Problems in chapter One Dimensional Consolidation of Geotechnical Engineering I

Answer 1

The correct option is (c) 400cm

For explanation I would say: Given, both the sample and the field layer has single drainage,

t1= 20 min

t2= 386 days

d1= 2.4cm

since, \(\frac{t_2}{t_1} =(\frac{d_2}{d_1})^2\)

therefore \(d_2 = d_1 \sqrt{\frac{t_2}{t_1}}=2.4\sqrt{\frac{386×60×24}{20}}=400cm=4m.\)