长壁机械化掘巷充填采煤围岩结构稳定性及运移规律
Study of stability of surrounding rock and characteristic of overburden strata movement with longwall roadway backfill coal mining
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摘要: 为解决西部生态脆弱矿区煤炭开采率低、采后环境易破坏等难题,提出了一种长壁机械化掘巷充填采煤方法。在系统阐述该技术方法的巷道布置与充填采煤工艺的基础上,分析了该技术的难点与关键。基于长壁掘巷充填采煤岩层移动特征,建立了长壁掘巷充填开采采场力学模型,推导出了采场顶板下沉方程与煤柱承受载荷计算公式,并结合极限强度理论,提出了煤柱失稳判据。以陕西榆林常兴煤矿3101工作面掘巷充填采煤为工程案例,通过充填体材料力学特性测试,优化设计了掘巷充填采煤开采方案。采用3DEC数值模拟软件对掘巷充填采煤上覆延安组层间裂隙承压水隔水层与第四系松散层孔隙潜水隔水层移动特征及稳定性进行了分析,现场应用案例表明,该技术可有效控制工作面围岩结构稳定性与上覆隔水层岩层移动,提高煤炭资源回收率,可为西部生态脆弱矿区煤炭资源开采与环境保护协调发展提供借鉴。Abstract: In China’s western ecological fragile coal mining area,the traditional coal mining technology causes many environmental problems with low coal recovery. To solve the problems and to improve coal recovery,the longwall road- way backfill coal mining method was proposed as a solution. Through the systematic analysis of the roadway layout and backfill mining technology,the difficulties and key points in the technology were shown. Based on the strata movement characteristics in the roadway backfill coal mining,the mechanical model of coal mining in stope was established. Then,the equation of roof deflection curve with corresponding mechanical analysis and the calculation formulas of coal pillar were calculated. And an assessment on the instability conditions of the coal pillars were also provided combining the ultimate strength theory. Combined with one engineering case of roadway backfill mining in Shaanxi Changxing Coal Mine,with the test results of backfill material mechanical properties,the mining plan of roadway backfill coal mining was optimally designed. At the same time,the 3DEC numerical simulation software was used to study and analyse the overlying strata movement of the water-resisting layer in Yan’ an Formation interlayer fissure confined water and the Quaternary loose pore phreatic water. Field application results show that this technology can effectively control the stability of surrounding rock and the overlying strata movement of water-resisting layer,improve the recovery rate of coal resources and provide a reference for the coordinated development of the western mining area resources and envi- ronmental protection.