错层位采煤法非常规区段煤柱稳定性理论研究

Theoretical analysis of stability of unconventional gateroad pillar employing longwall mining with split-level gateroads

错层位采煤法将采煤工作面两端的巷道布置于煤层中的不同层位,相邻工作面巷道立体交错,形成一种新型非常规区段煤柱。应用极限平衡理论建立了该区段煤柱力学结构模型,对其稳定性进行了研究,得到煤柱极限平衡区宽度表达式及其支承压力的分布规律,并根据研究结果得到煤柱应力区域划分规则。研究结果表明,这种新煤柱极限平衡区宽度明显减小,煤柱的稳定性和煤炭资源采出率得到提高;煤柱内应力多出两分区,即免压区(不受或仅受少量矸石的重力作用)和直接顶垮落矸石自重作用区。该研究在长壁开采煤柱设计、提高煤炭采出率等方面具有一定意义。

By adjusting longwall top coal caving panel,gateroads on either end of the LMSG( longwall mining with split-level gateroads) panel are arranged at different levels within a coal seam,gateroads of the adjacent panels are offset spatially,unconventional gateroad pillar was developed. A structural model of trapezoidal pillar in is established using limit equilibrium theory and stability of the pillar is analyzed. An analytical equation of the depth of plastic zone of the gateroad pillar is derived,and distributions of supporting stress are obtained. New division of the gateroad pillar is obtained according to the above results. The result shows that the depth of limit equilibrium zone within the gateroad pillar is tremendously reduced but the stability of coal pillar and recovery ratio are significantly increased. In addition,two additional zones within this coal pillar were found,stress free zone( where only subjected to no or slightly weight of gangue) and self-weight action zone resulting from immediate roof. The reseach has some significance in gateroad design and increasing recovery ratio,etc.