Question

The strength of sub-grade is increased by _________

(a) compaction

(b) swelling

(c) bulking

(d) addition of excess of water

I have been asked this question in an interview for job.

My question comes from Design of Flexible Pavements in chapter Design of Flexible & Rigid Pavement of Geotechnical Engineering II

Answer 1

Correct option is (a) compaction

Explanation: Compaction is a process by which the soil particles are compacted by loads into a closer state. This reduces the voids ratio which in turn increases the dry density of the soil sample. This increases the strength of the sub-grade.