降雨時の浸透挙動と斜面の不安定化について

Abstract

FEM saturated-unsaturated seepage flow analyses were conducted on slopes of soil layers with uniform thickness, to evaluate seepage behaviors during rainfall and their influences on instability of slopes by wetting. Direct causes of slope failures during rainfall are supposed to be the following two; one is the increase of the pore-water pressure due to the rise of the water table by rain, and the other the spatial difference of that to cause seepage failure such as piping. Main influential factors to be considered in the analysis are then listed as the configuration of slopes (height, inclination, thickness of layer), the strength of rainfall (ratio to the coefficient of permeability of soil), mechanical properties of soil (strength and deformation characteristics and strength reduction by wetting), and initial condition of soil layer before rain (initial degree of saturation and the effect of previous rain). Several patterns of calculations were made in this paper to evaluate numerical consequences of these influential factors against instability of slopes during rainfall.