Experiment Research on Shear Characteristics of Sandstone Considering Cyclic Drying-Wetting Effect

Based on shear tests of sandstone under the different times of drying-wetting cycle, the change laws of mechanical behaviors of sandstone such as shear strength, shear parameters and shear failure characteristic with cyclic drying-wetting effect were analyzed, and then the deterioration mechanism of shear property of sandstone under drying-wetting effect was discussed. The results show that there is a strong negative correlation between times of drying-wetting cycle and shear ability, the more the test times is, the lower the shearing strength and the shear parameters are. Moreover, through the comparison to the test curves, it is found that the cohesive force c is far sensitive than inter friction angle phi in the face of influence of drying-wetting effect. The failure characteristic is also affected by drying-wetting effect, the less test times is, the more obvious brittle failure, that is, with the strengthen of drying-wetting effect, the failure law of sandstone present a transformation from brittleness to ductility.