Question

When the pre-consolidation pressure σp‘ is greater than initial effective pressure σ’0 but smaller than effective pressure σ’, then the final settlement is calculated on the basis of ___________

(a) settlement due to σ’0 to σp‘ using CS only

(b) settlement due to σp‘ to σ’ using Cc only

(c) settlement due to σ’0 to σp‘ using CS and settlement due to σp‘ to σ’ using Cc

(d) settlement due to σ’ to σp‘ using Cc and settlement due to σp‘ to σ’ using Cc

This question was posed to me at a job interview.

My enquiry is from Consolidation Process topic in portion One Dimensional Consolidation of Geotechnical Engineering I

Answer 1

Right answer is (c) settlement due to σ’0 to σp‘ using CS and settlement due to σp‘ to σ’ using Cc

For explanation: In the determination of the final settlement by voids ratio, when the pre-consolidation pressure σp‘ is greater than initial effective pressure σ’0 but smaller than effective pressure σ’, then the final settlement is calculated using the two parts:

settlement due to σ’0 to σp‘ using CS

settlement due to σp‘ to σ’ using Cc.