Numerical analysis and application of stress corrosion model considering strain softening

Abstract

The deformation behavior of rock over time dominated by stress corrosion has been an important research topic for a long time. Based on the principle of stress corrosion damage rate and the concept of rock strain softening, a stress corrosion (SSC) model considering rock strain softening was proposed. The model describes the diameter degradation of inter-particle bond and bond fracture caused by stress corrosion in 2D and 3D scales, respectively. The adhesive particles with softening characteristics are used to compose rock samples, and the time-dependent failure analysis of rock aging characteristics is carried out by using adaptive time step. The results show that the SSC model can match the static fatigue test results of Lac du Bonnet granite and the ideal creep behavior curve. At the same time, the long-term stress corrosion failure time of granite is predicted and compared with the existing stress corrosion models and the stress corrosion failure time prediction data, the SSC model can better predict the long-term stress corrosion failure time of granite. In addition, flexible triaxial compression experiments coupled with FDM-DEM (finite difference method and discrete element) were carried out to verify the relationship between the reduction of soft bond diameter and the driving stress ratio of the SSC model. Finally, the SSC model is used to perform uniaxial compression experiments on rock masses with precast cracks, which provides reference for engineering cases from the mesoscale.