Investigation of shear creep experiments and modelling of mud-shale under dry-wet cycles of rainfall

Abstract

Abstract The analysis of the creep mechanical properties and the failure mechanisms of mud-shale in response to dry-wet cycles of rainfall are important for the slope stability of Permian limestone with carbonaceous mud-shale. In this paper, shear creep experiments were performed on mud-shale under different dry-wet cycles of rainfall. The classical viscoelastic-plastic creep model was improved and a modified creep model was developed to account for the damage of dry-wet cycles. The results showed that the creep deformation and the long-term strength of the mud-shale degraded with dry-wet cycles and promoted mud-shale failure. According to the macroscopic continuum damage theory, the viscoelastic-plastic model was modified considering the damage of dry-wet cycles, which fitted the mud-shale creep curve well. It was found that there was a good consistency between theoretical predictions of the VEPD model and the experimental dates, and the viscoelastic parameters exponentially decreased with dry-wet cycles in the VEPD model, especially G 1, η 1. The VEPD model could predict the complete creep process in mud-shale, which provided a great demonstration of the effect of dry-wet cycles on creep behavior. The model therefore enables a deeper understanding of the long-term stability of slope engineering projects.