EFFECT OF THE SOIL MOISTURE DISTRIBUTION AFTER RAINFALL ON SEISMIC STABILITY OF EMBANKMENT SLOPE

Abstract

Recent studies of sediment disasters have indicated that slope failure due to earthquakes was
affected by precipitation before the earthquake. Here, we focus on the effects of variation in soil moisture
conditions due to antecedent rainfall on slope failure due to earthquakes. To clarify the relationship between
the volumetric water content of soil with elapsed time after rainfall and the scale of slope failure, we
conducted a series of vibration loading experiments under different soil moisture conditions. In the
experiments, ‘rainfall’ was applied to the model slope using an artificial rain simulator, and the model slope
was subjected to seismic wave loading using a shaking table. Soil moisture and laser displacement sensors
were used to measure the volumetric water content of soil and displacement of the slope, respectively. The
results indicated that the top of slope collapsed and sliding failure occurred when the volumetric water
content of the soil was low. The crest of the model slope settled considerably without eroding the sliding
surface when the volumetric water content of soil was high. Our study indicated that the soil moisture
distribution has a significant influence on the scale of slope failure.