The disintegration mechanism analysis of soft rock due to water intrusion based on discrete element method

Abstract

Though many laboratory tests have been carried out on the effect of water content on the disintegration characteristics of soft rock, there are still relatively few numerical simulations that can well describe this kind of process. Based on the test results obtained by previous relevant research, the two-dimensional unconfined soft rock immersion test was numerically simulated by the discrete element method. The hydration expansion of clay particles is considered in the simulation. The breaking force and residual strength coefficient in MatDEM are selected to characterize the slaking durability of soft rock. Several groups of control sample models were set up, and the effects of crack, clay mineral content, and initial water content on the softening process of rock samples were discussed. The results show that the simulation in this paper is consistent with the process of infiltration and disintegration of soft rock after water immersion in relevant studies. The strength parameters show an exponential attenuation relationship with water content. The breaking force and residual strength coefficient of the complete sample change in a gradient from outside to inside with water content. In addition, the initial crack improves the permeability of soft rock samples and changes the distribution of water content, which has a significant effect on the slaking durability of soft rock. Soft rock samples with high clay mineral content are more prone to plastic softening. The slaking durability of soft rock decreases as the initial water content increases.