Peridynamic micro-elastoplastic constitutive model and its application in the failure analysis of rock masses

Abstract In the process of compression, rock exhibits post-peak strength, which means that the failure criterion of traditional bond-based peridynamics is not suitable for rock materials. The peridynamic constitutive function is mainly for homogeneous materials and functional materials, which cannot reflect the characteristics of the post-peak strength of the rock. Therefore, based on peridynamic theory, a micro-elastoplastic constitutive model considering the post-peak stage of rock mass under compression loading is proposed, and the loading-unloading path in the post-peak stage of the rock is considered. This model makes up for the disadvantage that the traditional peridynamics model cannot reflect the post-peak strength of rock. Considering that the nonlinearity of the mechanical properties is caused by the heterogeneity of rock materials, the nonuniform discrete method is used in the model, which further improves the accuracy of the numerical simulation. Using the micro-elastoplastic model, the rock specimens were numerically simulated in uniaxial compression tests and uniaxial cyclic load tests, while the flaw propagation of a single pre-existing flaw with different inclination angles under uniaxial compression was analysed. The numerical simulation results are in good agreement with experimental results, which verifies the accuracy and superiority of the new model.