卸压(排放)钻孔破坏半径的数值模拟分析

为获得卸压(排放)钻孔破坏半径的计算表达式,利用RFPA2D数值模拟软件,模拟了不同煤层强度、不同煤层压力、不同孔径对钻孔破坏半径的影响,通过理论分析和回归分析得出了钻孔破坏半径的变化规律。通过多个方案数值模拟,定量得出了破坏半径与煤层压力呈幂指数关系,与钻孔有效直径呈对数关系,与煤层强度呈反比;所得出的钻孔破坏半径的表达式可用于不同条件下计算瓦斯排放钻孔的有效排放半径和卸压钻孔的有效卸压半径。结果对于钻孔卸压防治矿井动力现象有重要的理论指导意义。

Numerical simulation analysis of destroyed radius by pressure-released(drainage) borehole

To obtain pressure-released (drainage) borehole destroying radius calculation expression, the effects on borehole destroying radius, which are made by different coal seam pressures and intensity and borehole diameters, are simulated using the RFPA2D. Then its variational rules are deduced by theory analysis and regression. Through some numerical simulations, these conclusions are drawn quantificationally. The borehole destroying radius is exponential relation with coal seam pressure and is logarithmic relation with borehole effective diameter, but is in inverse proportion to intensity. Sequentially, the effective radius of gas extraction and the effective pressure-released radius of pressure-released borehole are calculated by the borehole destroying radius expressions. The result has important theoretical guiding meaning for preventing mining dynamic phenomena.