Study On The Crack Propagation Experiments And Numerical Simulation Of Intermittent Jointed Rock Mass With Fillings

Due to the constant motion of the earth’s crust and development, rock medium shows a significant discontinuity with a large number of joints, fissures and other discontinuities interface. The presence of cracks change the mechanical properties of the rock, reduces the strength of the rock, and gives rock obvious anisotropic nature.In actual projects, joints often contain fillers, for example, Shuibuya Power Station and Langya Mountain Hydropower Station rock joints are filling joints, which, compared with unfilling joints, from the mechanical analysis, would reduce stress concentration of the surrounding areas and allow some certain amount of pressure. A small amount of existing experimental results also show that penetrating joints expansion law with filling is quite different from that without filling, for example, relevantly, the crack strength get improved, split point move to the end of the joints, multiple development of micro-cracks are more obvious. Research of influence of filling to three dimensional crack propagation and deformation is very rare.On the basis of previous research, this paper carried out research from the following aspects:(DWith fundamental material of cement mortar, adding a certain amount of rubber powder, a new type of rock-similar material was developed. Through physical and mechanical parameters testing, it was found that this modified mortars could meet the requirements of similar materials and can be used as an ideal materail;This paper used a new model that can precisely position preset cracks, improved the fissures production test technology, achieved formation and penetration of prefabricated cracks and improved the operability and accuracy of tests.(2)Produced preset cracks with different forms (different d/T penetration, different filling materials), tested it to the uniaxial compression experiment, studied the role of restorative materials on the failure modes of three-dimensional cracks by analysis of the different filling way to test the stress-strain curve shape, strength properties, preset cracksfrom the crack angle and expansion mode.(3)With three-dimensional acoustic emission positioning technology, this paper analyzed acoustic emission characteristics and failure mode of different restorative materials specimens under uniaxial compression loading conditions.(4)Used FLAC calculation software to do numerical simulation of the specimens with different filling materials, filling depth and compare test results to analyze failure mode of cracks.On the basis of above study, this paper discussed the damaging effects of restorative materials on the fractured rock, summed up the extended mode of cracks under the action of the filling material, and is of certain guiding significance to the actual project.