Seismic response of granular slopes using discrete element method simulations.

摘要

Slope stability is one of the important topics when designing earth structures in geotechnical engineering. Earthquakes often cause failure of slopes that were originally stable under static conditions. Failure of an earth dam, solid-waste landfill, and natural slope caused by an earthquake can produce significant losses. Several techniques have been developed to evaluate the seismic response of granular slopes. These techniques typically fall into one of the following categories, in order from low to high complexity: force-based pseduo-static methods, displacement-based methods (i.e., Newmark sliding block method), and stress-deformation analyses. Even though these techniques are used widely in the geotechnical engineering industry, they do not properly account for soil nonlinearity during shaking. In this study, a three-dimensional microscale framework utilizing the discrete element method (DEM) is used to examine the seismic response of dry granular slopes under different conditions of ground motions. The model is processed under the gravitational acceleration of 50g to decrease the total duration of the simulation and the dimensions of the model. The presented model inherently accounts for soil nonlinearity and damping in response to shear deformations. The essential characteristics of wave propagation including motion amplification and resonance were observed from the computational results. Permanent deformations along the depth of the slope were captured in the conducted simulations. The impact of amplitude and frequency of input motion on the response of the slope was examined under different conditions. Comparisons are made between the results from DEM simulations and results from existing methods that utilize the Newmark sliding block approach.