Numerical Simulation Of Coal Seam Hydraulic Extrusion Three Phases Coupling Research

The establishment of a mathematical model which considering the mechanical properties of non-uniformity coal-rock mass media, the nonlinear variation of permeability in the fracturing process of coal-rock at the pressure of the water and the solid, liquid, gas three-phase fluid-structure interaction in the process of coal-rock deformation and fracture with the basic theoretical of multi-phase seepage mechanics,coal-rock mass deformation and gas flow, seepage coupling and porous media fluid dynamic.Gives the numerical method and calculation process of coupled model which based on FEPG software, and the corresponding program files.To the Qinan, Lianghuai mine, coal mine344face as examination, using a mathematical model of the three-phase coupling the coal stress field modulus of elasticity, homogeneity, poisson’s ratio, friction angle, and seepage field porosity, permeability coefficient, permeability parameters,giving the numerical simulation of main technical parameters which include water injection pressure, injection time and sealing depth when press the coal mines with hydraulic extrusion which affect coal rupture and gas crowded row effect.The simulation results show:with the advance of water injection time, coal gradually damaged and then destroyed, the system of the fracture surface expand further, the coal’s capacity of permeability increased greater; high-pressure water fracturing coal and make coal mining workface to the direction of a certain displacement to improve coal relief width, reduce the stress of a certain range near the coal wall coal, coal gradually by the elasticity to the plastic.Through the analysis of simulation results, optimizing the face reasonable hydraulic extrusion technology parameter. The field test confirmed the technical parameters of hydraulic extrusion which optimized with simulation results can play a homogenizing effect of the working face gas concentration, and prove the correctness of the results of the simulation, and also a powerful description of the reliability and stability of the model.Use of the mathematical model can provide on-site test basis for coal mines about the hydraulic extrusion technology parameters, significant savings in manpower and resources, and improve production efficiency.