Stress recovery procedure for discontinuous deformation analysis

The discontinuous deformation analysis (DDA) has been widely applied for rock engineering problems due to its special features in modeling the discontinuous rock mass. A linear polynomial function is often used in the standard DDA to ease the complex contact determination between the blocks. This linear displacement function generates a constant stress field within a block, which cannot be effectively used to model the stress variation within a block and across the block interface, especially in the region with a large stress gradient. In this paper, a stress recovery procedure is proposed for those DDA blocks which are glued together. Such a procedure can improve the stress accuracy along the block interface, and can be used for more accurate contact determination. Two numerical examples are presented to study the stress accuracy of the proposed method, and the results show that the proposed stress recovery method provides a better accuracy than the direct DDA and the averaging method.