Peridynamics Simulation of Stress-Seepage Coupling in Hydraulic Fracturing of Rock Mass

Abstract:

The stress-seepage coupling mechanism of fractured rock mass is the theoretical basis of geotechnical engineering activities such as oil and gas exploitation， in-situ stress measurement， and geological hazard prevention and control. In this paper， based on peridynamics nonlocal effects， a material points double repeat cover theoretical model was proposed. Combining the advantages of peridynamics in simulating the solid material deformation and damage and groundwater seepage， a peridynamics simulation method of fluid pressure driven stress-seepage coupling in fractured rock mass was established by using a hybrid time integration scheme and applied to the simulation of water injection test of hollow cylinder to reveal the mechanism of initiation， propagation， and connection of hydraulic fractures. The effectiveness of the simulation method was verified by comparing the results of laboratory tests with traditional numerical methods. The simulation results show that the deformation and failure of rock mass in the hollow cylinder water injection test are completely driven by hydraulic power， and the generation of hydraulic fractures is random. Therefore， there is no need to specify the fracture propagation path. In addition， the energy causing the fracture of the specimen in the process of hydraulic fracturing has a process of accumulation and release， which can be well captured by peridynamics.