Physical effects of liquid-vapor water transition in unsaturated soils

Abstract

Collapsing of soil is the sudden reduction in volume under a certain overburden stress upon wetting. Wetting-induced collapse settlement canCP = + ( ) − − + 47 506 0 072 0 4393 123 2 851 . . . . ln( )− wi d w.γ (2)where, CP is the collapse potential in percentage; Cu is the coefficient of uniformity; wi is the initial moisture content (%); γd is the initial dry unit weight (kN/m3); pw is the pressure at wetting (kPa); and (S − C) is the difference between sand and clay contents (%). However, Habibagahi and Taherian (2004) found the above equations gave poor performance in predicting collapse potential, especially over smaller collapse potentials. This might be due to the fact that the use of inappropriate parameters and overlooking of some important parameters like matric suction, which may have a significant role in maintaining the meta-stable loose structure of collapsible unsaturated soil.