NUMERICAL SIMULATION OF ROCK RAPTURE PROCESSES UNDER THERMO-MECHANICAL COUPLING USING THE HYBRID PERIDYNAMIC AND FEM MODEL

Thermal shock induced fractures often occur in rock mass in the projects of geothermal, of oil and gas resource development, of deep mineral mining and, of underground nuclear disposal. Study on its rupture mechanism is of great significance for guiding the efficient and safe development of resources and for evaluating the stability of engineering structures. The Peridynamics (PD) method, a widely used non-local numerical approach in recent years, addresses the singularity and mesh-dependency issues inherent in traditional continuum mechanics when solving fracture problems. It is particularly well-suited for simulating material failure and fracture. However, due to its non-local nature, PD involves a relatively high computational cost. To mitigate this computational burden, this study presents a hybrid Peridynamic/Finite element model (PD-FEM) for simulating the deformation and failure behavior of rocks under thermo-mechanical coupling effects. The heat conduction problem of a pre-cracked plate is simulated, verifying the effectiveness and accuracy of the model in describing the discontinuity in the temperature field. The deformation of a high-temperature elastic plate subjected to low-temperature impact at the ends are solved. Convergence analysis is performed to provide quantitative criteria for the selection of discretization parameters. The rupture phenomena in high-temperature rock specimens with different initial temperatures subjected to unilateral low-temperature impact are simulated. The numerical results with initial temperature of 200 ℃ agree well with those from a reference paper¹, further verifying the capability of the model in simulating fracturing in rocks under thermo-mechanical coupling. The comparison of results for rock fracture at different initial temperatures shows that as the initial temperature increases, the number of cracks caused by thermal stress significantly increases under the same boundary low-temperature impact. This observation is consistent with the findings in the reference literature², demonstrating the accuracy of coupled model in simulating the rock fracture process under thermal shock. This work provides a novel method for studying rock failure processes under thermo-mechanical coupling through numerical simulations.