Study on Meso-Energy Evolution Law of Jointed Sandstone under Dry-Wet Cycle

In order to explore the meso damage and degradation law of jointed sandstone under the dry-wet cycles, the particle flow software was used to carry out the meso numerical simulation of jointed sandstone, and the meso mechanical properties and energy evolution mechanism of jointed sandstone under different dry-wet cycles were studied. The results show that the contact force between particles and the maximum value of parallel adhesion force decrease linearly with the increase of the number of dry-wet cycles; The crack evolution of jointed sandstone under dry-wet cycle mainly experienced four stages: slow increase, uniform increase, step increase and abrupt increase, and the number of cracks (total cracks, tensile cracks and shear cracks) was positively correlated with dry-wet cycles; The meso boundary energy, parallel cohesive strain energy and linear cohesive strain energy decrease gradually with the increase of dry-wet cycles. The dissipation energy in jointed sandstone is positively correlated with the number of microcracks; The dry-wet cycles action leads to the weakening of the fracture resistance between particles and the reduction of the energy storage capacity of rock samples, which is the energy mechanism that causes the dry-wet damage and deterioration of jointed sandstone.