Study On Two-Dimensional Displacement Discontinuous Media Model Of Jointed Rock Mass

After a long and complex geological age,the rock mass in nature has formed geological bodies with certain forms and different components under the complex physical and chemical changes,and many discontinuous planes have been formed in these geological bodies.In the upper crust,the most common rock formations are joints.If the rock has no obvious displacement at the fracture surface,the rock fracture surface is called joint.In the exploration method of wave propagation in jointed rock mass,displacement discontinuity method is a new method of time domain analysis,which is used to analyze the complexity of wave propagation.In this paper,the propagation law of wave in jointed rock mass is studied systematically with appropriate models,and the following research results are obtained:1.Compared with frequency domain analysis,time domain analysis has stronger intuitiveness,stability and anti-interference ability.Combined with mechanical parameter expansion analysis of jointed rock mass,the formation process and propagation law of stress wave in jointed rock mass have certain influence on rock mass structure.There is a functional relationship between the variables that affect the wave propagation and the attenuation of the wave velocity when the wave has oblique incident joints in different states.For example,the relationship between joint dip angle and stress wave peak velocity,stress wave and reflection coefficient,transmission coefficient and attenuation coefficient is analyzed.The results clearly show that the anisotropy of joints hinders the propagation of stress wave to some extent.2.For the nonlinear behavior of joint deformation,considering the wave propagation in the rock mass of multiple joints,when the wave propagates in multiple parallel joints,the propagation process is diverse and the transmission and reflection are complex.According to the wave propagation method in parallel jointed rock mass,the theoretical model of displacement discontinuous media propagation is established,and the propagation process of adjacent jointed rock mass is analyzed by time-domain recursion method,and the propagation equation of p-wave and s-wave oblique incident jointed rock mass is deduced.3.Wave attenuation is analyzed by mathematical method and MATLAB software.Through parameterized research,incident angle,joint spacing,wave velocity,joint number and other external factors are analyzed according to the derived equation,which all affect wave propagation among multiple joints.At the same time,more other factors,such as joint spacing,permeability,joint distribution,joint filling and other microscopic characteristics of rock,are considered,which will affect wave propagation.The results show that the mechanism and process of wave propagation in jointed rock mass are revealed through the establishment of two-dimensional displacement discontinuous medium model and the study of parameters.This method can be used to calculate the transmission coefficient and reflection coefficient,impact angle and loading time under different incidence conditions.Compared with the calculation results of other studies,the calculation results of this study have also obtained the law for reference.