Development and application of rock energy dissipation model in FLAC3D

Rock failure is an instability phenomenon driven by energy.Describing the rock strength and defor-mation behavior from the perspective of energy is one of the effective ways to evaluate the safety and stability of engineering rock mass.In order to enhance the applicability of energy-based theoretical models to analyze engineering problems,and accurately describe the real-time evolution and distribution law of energy during the whole process of deformation induced failure of engineering rock mass,conventional uniaxial and triaxial mechanical tests in this study were carried out by using GCTS (rock mechanics test system).Based on the energy conservation law and the finite difference theory,this study derived the finite difference equations for rock elastic and dissipated energies.A finite difference program for energy dissipation model was developed by using FISH language,leading to the secondary development of FLAC3D for the strain softening model and the improvement of the energy calculation module of software.Through the comparative analysis between laboratory tests and numerical results under different confining pressures,the developed energy dissipation model can effectively describe the deformation characteristics and post-peak failure path of rock.The model can be used to study the large post-peak deformation behavior of engineering rock mass,but more attention should be paid to the description of the con-solidation and plastic deformation in the pre-peak period.The model developed was used to simulate the evolution law of dissipative energy of surrounding rock during the whole process of deformation and failure of the deep roadway.The results showed that the concentration area of dissipated energy of surrounding rock is basically consistent with the main failure location of roadway.Based on the density of dissipated energy,the degree of shear damage of roadway surrounding rock pressure can be quantified,which is beneficial to evaluating the post-peak stability of the damaged surrounding rock.