Extended DDA with rotation remedies and cohesive crack model for simulation of the dynamic seismic landslide

The failure of earthquake-induced landslides generally involves four stages: tensile cracking, breaking of the substrate, shearing failure, and deposition of the sliding mass, which poses a challenge for high-accuracy simulation of such landslides. To resolve this issue, this paper presents an integrated algorithm by introducing a bilinear cohesive contact model into the proposed discontinuous deformation analysis (DDA) method. In the proposed DDA, the displacement mode of the original DDA is replaced by the multiplicative decomposition of the displacement to improve the distortion and false volume expansion of blocks with large rotations. The timely introduction of the bilinear cohesive contact model can better describe the peak-post softening behavior of rocks consisting of blocks. Finally, the extended algorithm is formulated and implemented in the source program of the DDA and then verified through typical examples. The results indicate that the proposed method can facilitate the generation of tensile cracks and effectively eliminate distortion and false volume expansion of blocks, demonstrating consistent results with the test or field investigation.