To reveal the damage and degradation mechanisms of mudstone in tailings reservoir slopes under complex environmental conditions, dynamic uniaxial compression tests, CT scanning, and scanning electron microscopy (SEM) were conducted to analyze the evolution of dynamic uniaxial compressive strength and structural damage mechanisms of mudstone under three typical environmental conditions, i.e., wet-dry cycles, freeze-thaw cycles, as well as wet-dry and freeze-thaw cycles. The results show that the dynamic compressive strength and dynamic elastic modulus of strongly weathered mudstone continuously decay with the increase of cycle number, and the deterioration rate gradually stabilizes after 80 cycles. Among those three environmental damage conditions, the coupling effect of wet-dry and freeze-thaw cycles brings the most significant deterioration to mudstone. After 100 wet-dry and freeze-thaw cycles, the dynamic compressive strength and dynamic elastic modulus of mudstone decrease, and the connectivity of pore networks increases remarkably, presenting a strong linear relationship (negative correlation) between porosity and dynamic compressive strength. Complex environments can reduce the effective bearing area and stress transfer efficiency of rock mass by accelerating pore expansion and crack propagation, thus eventually lead to structural damage and strength deterioration of mudstone. Relevant suggestions for slope reinforcement engineering of tailings reservoirs are finally put forward based on the research results.

rock mechanics  /  mudstone  /  tailings reservoir  /  slope  /  wet-dry cycle  /  freeze-thaw cycle  /  dynamic mechanics  /  microstructure