充填高度对覆岩运动与地表下沉影响的数值模拟研究

Numerical Simulation of the Influence of Filling Height on Overburden Movement and Surface Subsidence

为解决“三下”压煤问题,减轻地表下沉和地下水流失等生态环境问题,以山西某矿充填开采工作面为研究对象,通过理论分析和数值模拟方法,分析采空区充填高度不同时的地表下沉量、覆岩破坏情况和导水裂隙发育情况。研究表明:地表下沉量随工作面推进逐渐增大,随充填高度增加逐渐减少,充填高度达到3.5 m时地表下沉量仅有0.22 m,相比于不充填的情况,下沉量降低了94.78%;覆岩破坏情况方面,工作面上覆岩层塑性区面积随工作面的推进而增大,随充填高度的增加而减少,在充填高度为3 m时关键层塑性区未贯通,此时关键层仍具有承载能力;导水裂隙发育高度方面,导水裂隙主要分布在工作面和切眼上方,随着工作面的推进,导水裂隙先发育后闭合,随着充填高度的增加,导水裂隙发育高度逐渐降低,当充填高度为3.5 m时采空区中部上覆岩层导水裂隙几乎不发育。基于上述研究结果认为,该矿充填高度为3.5 m时,地表下沉量最小,覆岩塑性区和导水裂隙发育程度最弱,在降本增效的同时,地表沉降控制效果最优。

To address the"three-under"issue(mining under buildings,water bodies,and railways)and to alleviate ecological problems such as surface subsidence and groundwater loss,the filling mining face in a mine in Shanxi was taken as the research object.Through theoretical analysis and numerical simulation,the study analyzed surface subsidence,overburden failure,and water-conducting fissure development under different filling heights in goaf.The research showed that surface subsidence gradually increased with the advancement of the mining face and decreased with the filling height.When the filling height reached 3.5 meters,the surface subsidence was only 0.22 meters,94.78%lower than that of non-filling mining.In terms of overburden damage,the area of the plastic zone of the overburden strata on the working face increased with the advancement of the working face and decreased with the filling height.When the filling height was 3 meters,the plastic zone of the key layer was not conducted,indicating the key layer still had bearing capacity.As for the height of water-conducting fissures,the water-conducting fissures were mainly distributed above the mining face and the cutting eyes.As the mining face advanced,the water-conducting fissures developed and then closed.As the filling height increased,the height of water-conducting fissures gradually decreased.When the filling height was 3.5 meters,the water-conducting fissures in the overburden strata in the middle of the goaf were almost not developed.Based on the above results,it is believed that,when the filling height is 3.5 meters,the surface subsidence control effect is optimal while reducing costs and increasing efficiency,with the smallest surface subsidence and the least developed overburden plastic zone and water-conducting fissures.