Differential Swell of Unsaturated Clay caused byDifferent Wetting Conditions

Abstract

Abstract Wetting of compacted clays and their subsequent swelling, often results in damage to structures and infrastructures. Estimations of the swell expected to develop during wetting are usually based on standard laboratory tests. The standard procedure requires inundating the test specimens; this procedure represents an extreme wetting condition and provides an upper limit to the swell. However may result from less extreme conditions, for example by absorption of water due to suction forces, which may result in a smaller swell. This paper describes a laboratory investigation of the differential swell that may result from different wetting conditions. Swell tests have been carried out on specimens prepared at different initial conditions and wetted under different wetting conditions of inundation or absorption. The results indicate that as the initial void ratio decreases and degree of saturation increases, it is more likely that different wetting conditions will cause different swell magnitude. The soil at low initial void ratio and high degree of saturation seems to be characterized by mono-modal pore size distributions in the micropores range. This unique pore size distributions may be the explanation for the differential swell.