短-长壁工作面充填无煤柱开采方法研究

Short-and long-walls backfilling pillarless coal mining method

为减少传统煤层开采中隔离煤柱损失,同时提高无煤柱开采沿空巷道的稳定性,提出短-长壁工作面充填无煤柱开采方法。首先,沿运输大巷间隔布置短壁工作面和长壁工作面,短壁工作面等效于传统长壁工作面间的隔离煤柱;然后,采用条带充填开采的方式先回采短壁工作面,根据短壁工作面宽度不同,回采条带可以平行或垂直于短壁工作面长度方向布置,充填条带渐次置换短壁工作面实体煤,并形成宽充填柱,隔离相邻长壁工作面,同时支撑顶板岩层;最后,短壁工作面回采完毕后,开切眼,形成长壁工作面,长壁工作面布置形式同常规综采一致。此项技术的关键是条带煤柱/充填柱稳定性,按梁式和板式断裂2种情况推导开采条带宽度理论计算式,由Wilson理论推导煤柱/充填带宽度理论计算式。可行性分析表明:优化采煤与充填工序组织,可以实现割煤与充填工序分离,保障安全生产与提高采充效率;相比于原位沿空充填留巷、巷帮预置充填带等无煤柱开采方法,短壁工作面采空条带两侧有实体煤或充填体,采空条带充填无须大规模架设挡板(墙),接顶质量高,施工安全风险小、效率高;短-长壁工作面间断充填无煤柱开采技术经济效益明显;同时采用充填法回采长壁工作面,可同步构建储库,储存天然气、封存CO_(2)、压缩空气储能、抽水蓄能等,增加煤炭开采的附加社会经济效益。

To decrease the loss of panel-separated pillars in coal mining and improve the gob-side roadway stability of pillarless coal mining,an interval short-and long-walls backfilling pillarless coal mining method has been proposed. Firstly,the short-wall longwall panel and the long-wall longwall are arranged at intervals along the main transport roadway. The short-wall panel is equivalent to the panel-separated pillars in the traditional fully mechanized mining. Then,the short-wall is mined using strip backfilling mining method. The coal strip pillars can be parallel or vertical to the length direction of the short-wall panel according to the difference of working face width. The backfilling strips gradually replace coal strip pillars,and form a wide backfilling body which isolates the adjacent longwall panels and supports the overlying strata. Finally,a start-up room is excavated to form a longwall panel when the two adjacent short-wall panels have been mined. The layout of the long-wall panel is consistent with the conventional fully-mechanized mining. The key technique is the stability of strip or backfilling pillars. Therefore,the theoretical calculation formula of mining strip width is deduced according to beam type and plate type fracture models. Meanwhile,the theoretical calculation formula of coal/backfill strip pillar width is deduced based on the Wilson Theory. Feasibility analysis shows that the optimization of coal mining and backfilling sequences can realize the separation of coal cutting and backfilling process,ensuring safe production and improve efficiency. Compared with traditional pillarless coal mining methods,such as in-situ roadway backfilling retaining along goaf and presenting backfilling body along wide roadway wall,there are solid coal or backfilling bodies on both sides of the mined-out strip in the short-wall panel;Therefore,there is no need to build large scale building formwork or wall before mined-out strip backfilling,which means high quality roof-contacted and low safety risk,and high efficiency. The interval short-and long-walls backfilling pillarless coal mining technology can increase the economic benefits of coal mine. Besides,underground storages can be constructed simultaneously during the backfilling mining process of longwall panel to store natural gas,CO_(2),and compressed air with internal energy or water with potential energy.