STUDIES ON CONSOLIDATION BEHAVIOUR OF LAYERED SOILS

Abstract

The conventional Terzaghi’s 1D consolidation theory has neglected the effect of layered soil on consolidation behaviour. To overcome this limitation, numerous studies have been carried out by many researchers using the numerical and analytical methods. But very few researchers have done experimental work for observing consolidation behaviour in layered soil. In the present study experiments have been carried out to observe the behaviour of soil for two layered soil sample and for soil sample with different thickness without and with sand drain. The role of sand drain is to accelerate the consolidation process of soil. From these experiments it is observed for the layered soil, if soil with less coefficient of permeability and coefficient of volume compressibility is lying below the soil having greater coefficient of permeability and coefficient of volume compressibility, rate of consolidation decreases compared to single soil layer. It is also observed that as thickness of soil increases, compression index and swelling index decreases. This is because, as the thickness increases the friction between side wall of consolidometer and soil increases and total load is shared by soil and friction between soil and side wall of consolidometer. It is also observed that rate of consolidation increases when sand drain is installed in it. The consolidation behaviour of layered soil is then validated using Finite Difference method.