Abstract:
An energy storage meso-structure is proposed with meso-defects as the core and strain energy density isosurface as the outer boundary. The rock is considered as a system composed of meso-structures arranged seamlessly. The breakage evolution process of meso-structural system driven by energy is analyzed, and the mechanisms of plasticity, dilatancy, residual strength, confining pressure effect of rock and the formation mechanisms of weakened zone and orderly fracture surfaces are explained. The breakage process of meso-structural system is found to have the characteristics of dissipative structure, which can be considered as a dissipative structure. The nonlinear breakage mechanism inside the meso-structural system is analyzed, and the dynamics equation describing the breakage process of the meso-structural system with dissipated energy as the parameter is established. The dissipated energy evolution equation is derived and fitted with a large number of experimental results, with the average goodness-of-fit exceeding 0.97 which proves the correctness of the dissipated energy evolution equation and the feasibility of its establishment method. The breakage behaviors of meso-structures are characterized as the transformation of elastic-brittle cementation elements or cementation groups into the same number of elastic-plastic friction elements. Based on the energy dissipation process, the breakage parameter evolution equation considering the influence of confining pressure is established. The triple shear energy yield criterion is imported to describe the stress-strain relationship of friction element, and the incremental form of rock binary medium model is derived and embedded in finite difference software. Laboratory tests are simulated, and the results show that the proposed binary medium model can satisfactorily describe the mechanical characteristics of different kinds of rocks, such as stress-strain, dilatancy, confining pressure effect and brittle-ductile transition. The research results have important reference value and significance for the analysis of rock mass instability from the perspective of energy.