Question

During consolidation process of clayey soils, indicate the sequence of occurrence of the following events in the order from first to last

• A. 1, 2 and 3
• B. 2, 3 and 1
• C. 1, 3 and 2
• D. 2, 1 and 3

Answer 1

The correct option is C 1, 3 and 2

Consolidation of soil deposit has three stages:

1. Initial Consolidation : When a load is applied to a partially saturated soil, a decrease in volume occurs due to expulsion and compression of air in the voids.
2. Primary Consolidation : After initial consolidation, further reduction in volume occurs due to expulsion of water from voids. When a saturated soil is subjected to a pressure, initially all the applied pressure is taken up by water as an excess pore water pressure, as water almost incompressible as compared with soil particles.A hydraulic gradient develops and the water starts flowing out and a decrease in volume occurs. The decrease depends upon the permeability of the soil and is, therefore, time dependent. This reduction in volume is called primary consolidation.
3. Secondary consolidation : It occurs due to the plastic readjustment of the solid particles and the adsorbed water to the new stress system.