Effects of Rock Mass Deterioration Induced by Wetting-Drying Cycles on Slope Stability of Reservoir Banks

In view of the degradation of the rock mass mechanical parameters of the reservoir bank slope fluctuation zone caused by rainfall and the rise and fall of the reservoir water level, the moderately weathered sandstone of a slope in the Three Gorges reservoir area was selected as the research object. The “saturated” sandstone was subjected to Brazilian split test, uniaxial and triaxial compression tests. The test results show that the mechanical parameters of sandstone in the “dry” state are greater than those in the “saturated” state under the same number of dry-wet cycles (n); The uniaxial compressive strength, elastic modulus, tensile strength, cohesion, and internal friction angle of sandstone decrease logarithmically with the increase of n, and the Poisson’s ratio increases with the increase of n. The effects of dry-wet cycles have different degrees of degradation of different mechanical parameters of sandstone. As the number of cycles (n) increases, the envelope of the M-C rule in the π plane gradually moves to the center of the circle. In this paper, the M-C yield criterion of sandstone in two water-bearing states under different dry-wet cycles is revised. Sandstone is used as the representative rock mass, and the water-rock interaction of the reservoir bank slope rock mass under the condition of reservoir water fluctuation is simulated through experiments. During the process, FLAC3D was used to carry out a numerical simulation of bank slope stability under the action of water-rock circulation, which provided a useful basis for the stability analysis of reservoir bank slopes.