邯邢矿区承压水上充填采煤底板渗流规律研究

The seepage law of confined water in floor of backfilling working face in Hanxing Mining Area

为了掌握开采参数和充填参数对承压水上采煤工作面底板渗透破坏的影响机制,针对邯邢矿区承压水上安全采煤问题开展研究,基于典型矿井煤层地质赋存特征,建立了承压水上开采水岩耦合概化地质模型,分析了承压水上采场底板力学行为。根据半无限板集中荷载和均布条形荷载传播的求解方法及弹性力学叠加原理,获得了采动与水压共同作用下底板应力分布表达式。进而借助MATLAB计算程序,以邯邢矿区开采条件及实测数据为例,得到了有无水压条件下底板应力分布规律,采动应力等值线与奥灰水压力等值线相互交织、互相影响,加剧了对底板变形破坏的影响。进一步计算出了水岩共同作用下底板应力分布和主应力差分布,揭示了承压水上采场底板破坏与充填控制机理。通过散体矸石固体改性试验,得出了掺入自主研发的胶结料后改性充填材料力学性质,其弹性模量范围为30~50 MPa。岩石破裂数值模拟结果显示,当充填体弹性模量增加至50 MPa时声发射事件和累积释放能量明显减少,且采煤工作面底板仅出现少量裂隙并最终被控制在局部范围,不会出现失稳性扩展,充填体的抑制作用与承压水的破坏作用达到平衡状态。研究结果为邯邢矿区准备开展的30 m以内隔水层间距煤层开采提供了前瞻性理论基础。

In order to grasp the influence mechanism of mining parameters and filling parameters on the seepage failure of coal face floor over confined water,the research was conducted aiming at safe mining over confined water in Hanxing Mining Area.Based on the geological characteristics of coal seams in typical mines,the water-rock coupling generalized geological model of confined water mining was established and the mechanical behavior of stope floor was analyzed.According to the method of solving the propagation of concentrated load and uniformly distributed strip load on the semi-infinite plate and the superposition principle of elastic mechanics,the expression of stress distribution on the floor under the combined action of mining and water pressure were obtained.Then with the help of MATLAB calculation program,taking the mining conditions and measured data of the Hanxing Mining Area as an example,the distribution law of floor stress under the condition of water pressure or not was obtained.The mining stress isoline and the ordovician limestone water pressure isoline interwove and influenced each other,which aggravated the influence on floor deformation and failure.Furthermore,the floor stress distribution and principal stress difference distribution under the joint action of water and rock were obtained,and the failure mech-anism of stope floor was revealed.Through the laboratory test of solid modification of granular gangue,the elastic modulus of modified filling material ranges from 30 to 50 MPa.The numerical simulation results showed that when the elastic modulus of filling body in-creased to 50 MPa,the acoustic emission events and cumulative release energy were significantly reduced.Meanwhile,a few cracks ap-pear in the floor and were eventually controlled in a local range without instability expansion.The inhibition effect of filling body and the destruction effect of confined water reached a state of balance.The research results of this paper provide a forward-looking theoretical basis for the mining of coal seam spacing water within 30 m in Hanxing Mining Area.