Abstract
The permanent displacement of a slope in Noshiro city during the 1983 Nihonkai-Chubu earthquake is simulated by Distinct Element Analysis. The slope of 2.6 degrees average inclination and 200m length is modeled as 3180 element Distinct Element Model (DEM). A FEM model of 611 quadrilateral elements is utilized to verify the DEM model in the small displacement range. In quasi-static analysis using lateral seismic coefficients of 0.1-0.3, both FEM and DEM models are found to give similar failure surface and critical acceleration, i. e., threshold acceleration for initiating failure. Some subsurface layers are supposed to have been liquefied during the earthquake ground motion. In the model, both the stiffness and shearing resistance of these layers are reduced to account for their volumetric change and liquefaction. The movement of the slope due to subsurface soil liquefaction is simulated realistically with the DEM model including vertical crack and settlement at the top of the slope and lateral sliding of the surface layers. From parametric studies, volumetric change of the liquefied layer is found to be the most influential factor to induce deformation of the slope.
