岩石界面的动态剪切扩散行为OA北大核心CSTPCD

The diffusion behavior of shear instability control under dynamic load is the inducement for the development of local large deformation and the deterioration of macroscopic mechanical properties of rock.Firstly,the energy function of the unstable interface was established;and then based on the generalized variational principle,the interface disturbance analysis was carried out,while the first and second-order variances of the function were taken into consideration.Thus the governing equation of dynamic instability of the interface under shear load was established.Based on the discriminant equation,the influence of shear force and dynamic effect on the angle of the unstable interface is obtained.The results show that the angle of the shear deformation zone increases to a certain extent with the increase of external shear force.With the increase of the local dynamic coefficient,that is,the increase of the local inertial force,the shear band angle decreases obviously.By solving the diffusion equation with the edge displacement,the analytical expression of displacement was obtained,showing that the displacement increases gradually with the increase of loading time.To verify the reliability of the theoretical model and further study the deformation behavior of interface instability and its influence on wave propagation,the evolution of the fine and microscopic morphology of the contact surface during dynamic shear was described by combining with the SHPB rod-beam experiment technique,and an evaluation method for the influence of the evolution of surface contact parameters on mechanical parameters during interface instability was proposed.The numerical analysis model was established,and its result shows that interface instability is the leading condition of local shear failure slip.With the increase of interface thickness and shear force,the local displacement increases.The interfacial shear diffusion behavior greatly reduces the amplitude and changes the frequency of the transmitted wave.This study provides a good theoretical reference for the study of localization deformation and dynamic strength of rocks.