Study And Application Of The Interface And Weaken Method In FLAC3D Fault Simulation

This thesis sets the Fx26 fault of Tong Ting mine as the background, Theoretical analysis, numerical simulation and physical experiment were used to study the problem of FLAC3 D fault simulation. This paper summarized the numerical simulation principle and the specific steps of FLAC3 D, analyzed the method, principle and matters needing attention in FLAC3 D fault simulation; mechanics parameters of typical rock were obtained through laboratory tests, analyzed influence law of various parameters in fault simulation, put forward reasonable methods to determine the parameters; Based on mechanical analysis, deduced motion expression when the fault occurred stick slip, studied the working face pass oblique fault through the hanging side used interface method, and obtained the evolution law of regional stress. The main achievements are as follows:(1) Summarized specific steps and some matters needing attention of FLAC3 D numerical simulation, and improved the method of ―FLAC3D-CAD-ANSYS‖ and take FLAC3 D simulation results into excel, Tecplot, and reasonably solved the key problems of rock block, coordinate transformation, data output in operation process.(2) Obtained the influence law of the interface and weak-face parameters in fault simulation: with the increase of stiffness, the stress concentration degree of the fault end reduced gradually, cohesion and friction has little effect; with the increase of weak-face parameters, the stress concentration degree decreased gradually, with the increase of friction, simulation speed accelerate, and decreased with the increase of the cohesion and the elastic modulus, tensile strength almost had no influence.(3) Putted forward more scientific and reasonable method of determining the interface and weak-face parameters. According to the principle of same engineering case has the same stress environment, two kinds of fault simulation method was carried out, through the analysis and comparison of simulation results under different program to determine the relevant parameters. In this case, the interface stiffness should be taken 0.005 times of the surrounding elements stiffness, friction of the interface and the weak-face should be taken half of the friction of mudstone, the remaining parameters should be taken 1/20 of mudstone.(4) Based on the previous research results, obtained the evolution law of regional stress when the working face pass oblique fault through the hanging side by simulation study: abutment pressure of working face increases before pass the fault,then decreases and becomes stable after passed the fault; with the working face advanced to the fault and the stress concentration degree of fault end increases gradually, the stress release and reduced gradually when the working face through the appropriate location, when the working face crossing fault, and fault prone to slippage instability; The vertical stress along the working face presents decrease, suddenly increase, then decrease, finally increases and tends to be stable.