水压-应力作用下井筒围岩的破坏机理与控制研究

Failure mechanism and control of underground wall rock under the effect of water pressure stress

本研究结合曹家滩煤矿井筒围岩在穿越地层时受到了水压弱化作用的实际情况,采用查阅资料、现场查勘、理论分析、公式计算、数值模拟等研究方法,开展了该煤矿主斜井围岩在水压-应力作用下的变形破坏与控制研究。利用半圆拱形井筒断面等效表示的当量半径法,结合地层水压、侧压系数、埋深、内聚力、内摩擦角、巷道尺寸等因素,优化建立了井筒围岩塑性区分布的数学表达式,并进行了模型的数值模拟验证与公式的敏感性分析,针对层位岩性差异及水压弱化作用等主要控制因素,从抑制围岩剪切破坏发生、提高围岩内聚力及内摩擦角、开孔泄水降压、注浆驱替水源、加强原有支护的角度进行了井筒的水害治理与围岩控制。对掌握井筒周边围岩在水压-应力作用下的变形破坏规律、开展相关的数值模拟研究、进行井筒的加固与水害防治工作具有一定的参考意义。

Based on the actual situation at Caojiatan Coal Mine,that the wall rock of the opening is weakened by water pressure while crossing the stratum,we did deformation,failure and control research on the surrounding rock of the main inclined opening under the hydraulic stress effect by means of data review,field investigation,theoretical analysis,formula calculation and numerical simulation,etc.To employ the equivalent radius method of semi-circular arch opening section,combined with the factors,such as formation water pressure,lateral pressure coefficient,buried depth,cohesion,internal friction angle and roadway size,we designed an optimized mathematical formula of plastic zone distribution in shaft surrounding rock,and made the numerical simulation and the sensitivity analysis of the formula.Aiming at controlling stratum lithology difference and water pressure weakening,the water damage control and surrounding rock control of shaft are carried out from the aspects of prohibiting wall rock shear failure,improving the cohesion and internal friction angle of surrounding rock,opening water discharge and pressure reduction,grouting to replace water source,and strengthening the original supports.It will be a certain reference for the research on the deformation and failure law of surrounding rocks under water pressure stress,on the relevant numerical simulation study,and on openings reinforcement and water disaster prevention and control.