浅埋煤层大采高工作面顶板破断角实测研究

Field-measurement study on roof breaking angle of working face with large mining height in shallow coal seam

基于弹性力学和岩石力学,给出了浅埋煤层顶板破断角的理论计算公式,并在张家峁煤矿22201工作面辅助运输平巷施工9个钻孔,采用钻孔窥视确定了顶板的破断位置,得出了大采高工作面的顶板破断角,结合物理模拟实验对结果进行了验证。研究表明:理论分析得出浅埋煤层采场顶板破断角范围为56.2°~69.3°;现场实测得出22201大采高工作面顶板10~30 m层位的顶板平均破断角约为68.3°,根据物理模拟实验得出的大采高工作面顶板10~30m层位的顶板平均破断角约为66°,理论计算和现场实测、物理模拟实验结果吻合。此外,对浅埋大采高工作面周期性破断角的物理模拟实验统计分析,当采高M≥6m时,顶板破断角在64°~68°,与理论计算偏差在6%之内,表明理论计算公式具有较高的可靠性和适用性。

Based on theories of elastic mechanics and rock mechanics,the theoretical calculation formula of roof breaking angle in shallow coal seam was developed.Nine boreholes were drilled in 22201 working face of Zhangjiamao coalmine.The roof breaking location of overlying strata was determined by using drilling peeping.Meanwhile,the roof breaking angle of working face with large mining height was obtained.Results were verified by physical simulation experiments.It could be obtained that the range of roof breaking angle is 56.2°~69.3°.In contrast,field measurement shows that the average breaking angle of 10~30 m overlying strata of 22201 working face is 68.3°.The corresponding roof breaking angle obtained by physical simulation experiment is 66°.Therefore,breaking angles in the theoretical calculation,field measurement and physical simulation experiment basically are consistent.In addition,statistical analysis of physical simulation experiment on periodic breakage angle of working face with large mining height in shallow coal seam was conducted.When mining height M≥6 m,the roof breaking angle is 64°~68°,and its deviation from theoretical calculation is within 6%.It shows that theoretical calculation formula in this study has high reliability and applicability.