A simplified model for the evaluation of the degree of saturation in slope stability analysis of shallow soils

It is well known that the degree of saturation of a soil is time-varying in consequence of atmospheric conditions. Experimental data of matric suction at a site in Pilastro, Parma, Emilia Romagna Region, Northern Italy, have been used to compare against a simplified model, which is able to directly correlate the degree of saturation of a clayey-silt soil with rainfall events. The paper deals with the in-situ measurements of matric suction, the procedure to obtain the degree of saturation on the basis of assumed soil-water retention curves and comparison against the simplified model. This model, in turn, has been introduced in a simplified physically based stability method, recently set up by the authors to describe the most important factors influencing the rainfall-triggered mechanism of shallow landslides. © 2008 Taylor & Francis Group, London.