Question

FIGURE Q1 shows an example of construction failure of deep foundations which can be avoided through proper sub-surface investigation. Define the type of soils attributed to such geotechnical failure and propose THREE (3) possible solutions to remediate the problem. (13 marks] FIGURE Q2

Answer 1

Soil which leads to failure of deep foundation is expansion clay type of soil.This type of soil can absorb a good quantity of water in it which further swells us the soil. Due to this tendency of soil to absorb water, in summer the soil expands where as in less temperature it contract due to this response of expansion and contractions differential settlement occurs which leads to pile failure.

Sandy soil also have these type of settlement but less than that of clayey soil.

Remedies can be

Providing underpinning for the foundation.

By increasing the level of foundation, taking down deep to avoid soil shrinkage.

By removing vegetation from area and filling cavity area.

By proper characterisation of soil type.