Analysis of rupture propagation in overlying soil due to fault movement

Permanent ground deformation induced by fault movement is one of the main reasons for structural failure during an earthquake, especially for the failure of lifeline structures. Investigation of deformation and rupture propagation in overlying soil subject to fault displacements is the basis for predicting permanent ground displacements and analyzing fault risk. In this paper, rupture propagation in overlying soil under dip-slip fault displacements is investigated with finite element method, and a finite element model is developed for the overlying soil with excitation of the dip-slip fault displacement. The evolution of rupture propagation through overlying soil is simulated, and the effects of some parameters, such as loading rate, soil characteristics, dip angle of the fault, are estimated. The result shows ① the higher the dip angle of fault is, the bigger vertical displacement would be required to cause surface rupture; ② loading rate of the fault have some effects on the vertical displacement required to cause surface rupture and on rupture angle of soil because of inertial force; ③ the type of fault has significant effects on the relation between rupture angle of soil and dilatancy angle, as well as between rupture angle of soil and friction angle. The results presented in this paper could be referenced in earthquake resistant design of new structures and reinforcement of the existing structures.