An efficient remedy for the false volume expansion of DDA when simulating large rotation

Abstract

Although the constant strain mode of blocks assumed in the conventional discontinuous deformation analysis is sufficient for most applications in geotechnical engineering, a false volume expansion will occur in the presence of large block rotation. By introducing higher-order approximation to the displacements, the existing remedies can mitigate the false volume expansion to a limited extent; however, large acceleration variation or large rotation can still produce great errors. By fixing a local frame onto each block that moves and rotates with the block, the incremental strain components at the end of each time step are transformed to the local frame, which are then added to the total strain components with regard to the local frame. The false volume expansion is completely overcome with this method.