Abstract: Lots of shallow landslides in residual soil slopes are triggered by rainfall every year in Southeastern coastal area of China. Prediction of the rainfall-induced landslides is a hot research topic. Rainfall intensity-duration curve(I-D curve for short) is used commonly by previous researches to predict the landslide induced by rainfall. Firstly, the geological conditions of residual soil slopes and climate condition in Southeastern coastal areas of China are presented. Then the cross-sections and engineering properties of the residual soil slopes are presented. A finite element software, Geo-Studio, is used to study the effects of the initial moisture condition, shear strength, saturated permeability coefficient, slope angle, thickness of residual soil layer and rainfall pattern on I-D curve. Results from the parametric analyses show that shear strength, slope angle, saturated permeability coefficient and rainfall pattern influence the I-D curve significantly. With a decrease in shear strength, an increase in saturated permeability coefficient or an increase in slope angle, the rainfall duration causing a slope failure shows a decreasing trend. The influence of initial moisture condition on I-D curve is significant when rainfall intensity is lower. When rainfall intensity is larger than saturated permeability coefficient of the residual soil layer, the infiltration capacity is controlled by permeability coefficient; the rainfall duration causing a slope failure doesn’t change with the increasing of rainfall intensity. The research results can provide a basis for the application of I-D curve to predicting rainfall-induced landslides in residual soil slope in Southeastern coastal areas of China.

Key words: rainfall, residual soil, shallow landslide, rainfall intensity-duration curve, Southeastern coastal area