Review of collapsing soils

TLDR: In this article, it was shown that most of the collapse occurs at optimum clay content (10% in one case) and moisture content (between 13% and 39%) and that the amount and rate of collapse is a function of grain shape, grain size, existing moisture content, kinds and amounts of clay present, void ratio, adsorbed ions, etc.

Abstract: Soils which collapse (undergo large consolidation) when unusual amounts of water are added to them exist in many places around the world. Contrary to the ideas of many observers these collapsing soils derive from many different soil forming processes. Although surface collapse of 15 ft has occurred, the usual amount is considerably less. These soils are of open structure and exist in nature at less than 100% saturation. The major soil materials are silt, sand, or gravel or any of their combinations. Water in tension is the general binding material. A small amount of clay is present in many cases. Other binding agents sometimes contribute. The amount and rate of collapse is a function of grain shape, grain size, existing moisture content, kinds and amounts of clay present, void ratio, adsorbed ions, etc. Maximum collapse occurs at optimum clay content (10% in one case) and moisture content (between 13% and 39%). Most of the collapse can occur before the soil reaches 100% saturation. Estimates of the magnitude of possible collapse derived from routine tests generally are compared to field results.