Dissipative Structure Theory Analysis of Rock Deformation and Failure Process and Damage Constitutive Model

Rock is considered a system, and the energy mechanism is analyzed during the rock system turning into an orderly dissipative structure; the relationship and law between energy evolution and strength variation along with defect system evolution are disclosed. The nonlinear dynamic equation based on dissipated energy that describes the defect system’s evolution is established, which can deduce the evolution equation of dissipated energy. The nonlinear least square method is used to analyze the data of the dissipated energy from the compression tests of different kinds of rock under different confining pressures to verify the accuracy of the evolution equation of dissipated energy. The damage evolution law is established based on energy dissipation, which can reflect the energetic and mechanical mechanism inside the rock. A three-dimensional damage constitutive model that considers rock’s residual strength is constructed under continuum damage theory. The achieved theoretical stress-strain curves by the damage model are comparatively analyzed with the curves from the tests of different kinds of rock; the results indicate that the proposed constitutive model can describe the strength and deformation behaviors of rock material under a complex stress environment.