Remedies for Distortion and False Volume Expansion Problems with Large Rotation in Discontinuous Deformation Analysis

When simulating large rotation, the false volume expansion and elastic distortion problems of the block occurs severely in the original discontinuous deformation analysis (DDA). In this study, a new displacement formula that the elastic-deformation terms calculated before rotation is introduced. The formula is then linearized and used to modify the correlation submatrices. After each calculation step, the coordinate transformation is adopted to update the initial stress and strain-velocity vector. In the proposed remedies, the deformation of the block produced by centrifugal and Coriolis forces is considered automatically, and each of the deformation parameters has clear physical meaning. We further use several numerical examples to verify that the proposed method can eliminate the elastic distortion and false volume expansion problems exhibited by the original DDA. Finally, a real landslide case was analyzed to illustrate that the modified DDA is effective and useful. (C) 2020 American Society of Civil Engineers.