Mechanical Characteristic Experiment And Particle Flow Code Of Jointed Rock Samples Based On 3D Printing Technology

Engineering rock mass is often cut by various structural planes.The existence of structural planes makes rock mass have the characteristics of discontinuity and nonuniformity,which is also the biggest difference between rock mass and other engineering media.Therefore,the engineering properties of jointed rock mass are the basis of studying engineering rock mass.The existence of structural planes reduces the mechanical strength of rock mass by a large margin.At the same time,the structural planes in rock mass play a controlling role in the deformation and failure of rock mass.In many structural planes,the number of joints in rock mass is much higher than that of faults.The failure of jointed rock mass largely depends on the properties of joint planes.Therefore,the main mechanical properties of jointed rock mass are closely related to the strength characteristics of joints.The mechanical properties of rock joints under complex geological conditions are the basic scientific problems of rock mechanics.Accurate understanding of the compressive strength of rock joints under complex conditions is the basis for evaluating the stability of rock mass engineering and an important guarantee for ensuring the safety of large-scale engineering construction.In this paper,the artificial rock joints are taken as the research object,and through the combination of experimental and theoretical analysis,the following main research work is planned to be done in view of the current situation that the uniaxial triaxial compressive strength of rock mass with joint roughness is seldom studied and not in-depth,and the needs of practical engineering.(1)Five kinds of joint surface roughness(JRC = 2,7,12,17,22)and five kinds of joint surface dies with different inclination angles(0,30,45,60 and 90 degrees)were fabricated by using fractal dimension to describe the joint surface roughness coefficient.On this basis,joint rock samples with different JRC values and joint inclination angles were prefabricated.(2)Conventional triaxial compression tests of rock specimens under different joint inclinations,joint roughness coefficients and confining pressures were carried out by using high temperature and high pressure rock triaxial compression apparatus.The effects of joint inclination,joint roughness and confining pressure on the macrostrength and deformation characteristics of rock were discussed.At the same time,combined with acoustic emission and digital photography measurement technology,the jointed rock was revealed.The mechanism of crack evolution.(3)The conventional triaxial compression tests of simulated specimens are carried out by using PFC2 D discrete element program.The variation of macro-mechanical properties with joint roughness,different media,joint inclination and confining pressure is analyzed.The micro-mechanical response mechanism of crack propagation under different compression conditions of jointed rock mass is revealed.The simulation that is difficult to obtain in laboratory tests is emphatically analyzed.The results,such as the development characteristics of microcracks,the distribution of micro-stress field and micro-displacement field at the joint surface,further verify and supplement the experimental results.