Effects of cyclic wetting-drying on the mechanical behavior and improved damage model for sandstone

Abstract

The degradation of rock mechanical behavior after cyclic wetting and drying could affect the stability of rock slope, embankment, and tunnel significantly. A series of tests were first conducted on sandstone collected from a reservoir bank slope. The results showed that the mechanical parameters (including tensile strength, uniaxial compressive strength, elastic modulus, and internal friction angle) decrease as the cyclic number of wetting and drying increases. Then, a damage variable, which can consider the combined influence of cyclic wetting-drying and loading, was first proposed based on test results. Further, an improved damage model, which considers the effect of cyclic wetting-drying on internal friction angle and the nonlinear deformation characteristics in the fissure closure stage, was established with statistical damage mechanics. The determination method for the parameters in the proposed damage model was also introduced. Finally, the effectiveness of proposed model was verified by comparing with experimental data. The verification indicates that the results from the improved model agree well with test results, and the improved model can enhance the prediction accuracy over the original model.