DEM simulation of reverse faulting through sands with the aid of GPU computing

Abstract

This paper presents the results of analyses of a Discrete Element Methodology (DEM) developed to study reverse faulting through sandy layers, considering the inherent ability of DEM to model strain localization phenomena in granular soils; the paper emphasizes on engineering significances of the results. An efficient DEM code is implemented on Graphic Processor Unit (GPU) using CUDA architecture in order to reduce significantly the computation effort of present DEM simulations. The results of sensitivity analyses show that the average inclinations of the reverse fault ruptures increase by increasing both fault dip angle and soil ductility, due to the variations of the maximum principle strain directions and dilation angles along the fault ruptures. This causes that the corresponding fault ruptures outcrop the ground surface at nearer distances from the projection of the fault trace in the bedrock on the ground surface. In addition, the results indicate that the fault ruptures in denser sand create higher gradients on the ground surface at outcropping locations compared with looser sand, causing more serious damage to adjacent structures. Moreover, the minimum bedrock displacement required for the rupture to reach the ground surface is evaluated adopting an internal energy criterion, being proportional to the soil ductility. In addition, the results show that the limits of distortion zones on the ground surface shift generally toward the hanging wall by increasing the fault dip angle.