Instability Mechanisms and Reinforcing Treatment of Granite Residual Soil Slope Under Rainfall Infiltration Condition

Seepage field and stability on typical slope covered by unsaturated granite residual soil under rainfall infiltration condition are analyzed based on saturated-unsaturated seepage theory.Results show that maximum pore water pressure and volumetric moisture content in surface soil on slope increase with increased rainfall intensity and duration and present an increased large-small-large trend down slope.Slope stability significantly declines in initial rainfall stage and the downward trend changes slowly to a stable value with increased rainfall duration.When rainfall duration is short,rainfall intensity only changes pore water pressure distribution and water content in surface soil on slope.So the effect of rainfall intensity on shallow slope slipping can not be ignored.Because matrix suction can greatly influence slope stability,impact of suction on slope stability in engineering design should be considered.