Development of 1D bounding surface model for lattice spring model on predicting rock failure under cyclic loading

Abstract

A sound interpretation of the deformation and failure of rock material subjected to cyclic loadings is of great importance when predicting the long-term stability of rock structures. The bounding surface model is generally utilized to depict the mechanical behaviour of rock subjected to cyclic loadings. In this work, a simplified 1D bounding surface model is developed into a 4D lattice spring model (4D-LSM) to predict rock failure under cyclic loading. To better represent the nonlinear behaviour of rock material, a microcrack model is also introduced in the simplified 1D bounding surface model, together with a macro strength criterion and a cohesive zone model to represent the failure process of the rock. GPU-based parallel computing is realized to accelerate the time-consuming numerical simulation. The numerical results indicate that the proposed model reproduces the deformation and failure process of rock material under different cyclic loading paths. Moreover, the fatigue life of the rock under different conditions is predicted, including different stress levels, confining stresses, and preexisting macro joints. These numerical results reveal that the simplified 1D bounding surface model not only satisfactorily describes the mechanical response of rock under cyclic loading (like in classical continuum-based constitutive models) but also shares the advantage of the discrete-based numerical model in modelling the fracture and failure processes of rock under cyclic loading. This approach could also be used in other discrete numerical models, such as the discrete element model (DEM).