DEM Simulations of the Seismic Response of Flexible Retaining Walls
In this study, a three-dimensional analysis of soil-retaining wall dynamic interaction is conducted using the discrete element method (DEM). In this method, soil grains are treated as rigid spherical particles which are allowed to overlap one another at contact points. The forces and motions inside the assembly are calculated utilizing Newton’s second law of motion together with force-displacement laws. The deformable sheetpile-type retaining wall is simulated using rigid balls glued together by parallel bonds with specific strength and stiffness to mimic the physical properties of the real wall. Due to computational limitations, the high g-level concept and scaling laws for dynamic centrifuge testing are employed to decrease the domain size and simulation time. In addition, absorbing boundaries are employed at lateral sides of the model to prevent the reflections of the propagating waves back to the assembly. Seismic excitation is introduced to the system through the base wall, which represents the bedrock. The effects of different characteristics of the input seismic wave such as its frequency on the dynamic response of soil-sheet pile system are analyzed. Furthermore, data on lateral thrust and bending moment on the wall as well as its deflection is collected. It is shown that the numerical method is a competent tool to evaluate and predict the dynamic response of soil-sheet pile systems.
Keywords: Seismic effects, Three-dimensional analysis, Discrete element method, Soil analysis, Walls, Retaining structures