Dynamic boundary setting for discrete element method considering the seismic problems of rock masses

The discrete element method (DEM) provides an effective approach to analyse the large deformations and discontinuous problems in geotechnical engineering. In this paper, to improve the capability of DEM for seismic response analysis of rock masses, the problem of boundary setting in DEM is systematically investigated. Three typical dynamic boundary conditions are reviewed and introduced into DEM. Calibration factors are introduced into the equations of the boundary conditions, and an approach is proposed to determine the factors for optimum wave absorption. The procedures for constructing the free-field domain and main-grid domain are proposed. The seismic dynamic input methods are researched, and a static-dynamic unified boundary technique is proposed to enable the consistent boundary transformation. Numerical examples are presented to verify the feasibility and effectiveness of the proposed boundary-setting methods.