DEM simulations to study the effects of the ground surface geometry on dip-slip faulting through granular soils
This paper presents results of a study on effects of the ground surface geometry on propagation of dip-slip faulting through granular soils, using a GPU-based DEM methodology which incorporates rolling resistance. For this purpose, four ground surface geometries, including flat, trapezoidal, upward sloping and downward sloping are subjected to normal and reverse faulting. Then, the effects of the ground surface geometry on parameters such as average slope of the rupture and the fault outcropping strain are studied comprehensively. In addition, the results of the model are compared with Roscoe’s theory and this theory is used to explain some aspects of the results. The findings of the study show that the average slope of the rupture, regardless of the faulting type, faulting angle and ground surface geometry, is equal to the corresponding average slope of the zero-extension line along the rupture. This is in agreement with what the Roscoe theory predicts regarding the rupture (shear band) orientation. Moreover, the results show that the rupture path induced by normal faulting is not altered significantly by the ground surface geometry. However, the rupture path induced by reverse faulting is affected by the ground surface geometry through the change in directions of maximum principal strains within the soils deposit, according to the Roscoe theory.
Keywords: Discrete element method, ground surface geometry, dip-slip faulting, Roscoe theory, average slope of rupture, fault outcropping strain