Stability analysis of sloping grounds in unsaturated soils using the method of stress characteristics

An extension of the slip line theory to unsaturated soils is presented and applied to the problem of stability of slopes in unsaturated soils. The matric suction is then introduced and implemented in governing equations by the well-known Bishop effective stress concept. In this regard, the van Genuchten model is utilized to estimate the effective stress parameter required for the computation of the effective stress. The influence of the soil matric suction on the stability of slopes has been investigated for a variety of soils under steady state evaporation and infiltration, i.e., the distribution of the matric suction was assumed to remain constant with time. In addition, a measure of stability in terms of some factor of stability has been introduced.