Surface collapse control under thick unconsolidated layers by backfilling strip mining in coal mines
Surface collapse control under thick unconsolidated layers by backfilling strip mining in coal mines
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DOI：
10.1016/j.ijrmms.2018.11.006
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发表时间：
2019-01-01
影响因子：
7.2
通讯作者：
Ren, Mengzi
中科院分区：
文献类型：
--
作者：
Wang, Feng;Jiang, Bangyou;Ren, Mengzi
地下矿山开采引起的地表沉陷对生态环境和人类生活造成重大影响。地表塌陷是极其危险的，通常在没有预警的情况下发生。在中国，位于厚松散层下的煤矿在开采过程中发生了多次地表塌陷。通过对承载结构（疏松层中的拱结构和岩层中的关键层）对岩层移动影响的稳定性分析，揭示了地表塌陷的形成机理以及采动长度和采动高度这两个关键参数的作用。推测在长壁开采过程中，随着开采长度和开采高度的增加，承载结构不能自稳，会发生坍塌。结果导致长壁工作面采空区地表塌陷，并伴有承载结构破坏。考虑到这些风险，本研究提出了通过确定适当的长壁工作面长度和开采高度来防止承载结构破坏，从而避免地表塌陷的回填条带开采方法。在国内某较适合的厚松散层下煤矿进行了现场试验。观测到的地表最大沉陷仅为0.369 m，比长壁工作面（LW） 3A04减小了92%。开采过程中未发生地表塌陷。因此，我们的研究结果表明，该技术可以成功地防止厚松散层下长壁开采的地表塌陷。
Surface subsidence induced by mineral extraction from underground mines can significantly affect the ecological environment and human life. Surface collapse is extremely hazardous and typically occurs without warning. In China, numerous surface collapses have occurred during mining operations in coal mines located under thick unconsolidated layers. Via analysis of the stability of the bearing structure (arch structure in unconsolidated layers and key strata in rock strata) based on their effects on strata movement, our study reveals the formation mechanism of surface collapses and the roles played by two critical parameters: mining length and mining height. It is speculated that the bearing structure cannot be self-stable and will collapse during longwall mining with increasing mining length and mining height. As a result, the ground surface will collapse on the longwall face gob accompanied by the failure of the bearing structure. With these risks in mind, this study proposes a backfilling strip mining method via determination of the appropriate longwall face length and mining height to guard against bearing structure failure and thus avoid surface collapse. A field trial of the technique was conducted at a suitable Chinese coal mine located under thick unconsolidated layers. The maximum surface subsidence observed was only 0.369 m, which is 92% less than the subsidence in longwall face (LW) 3A04. No surface collapse occurred during the mining process. Thus, our results indicate that the proposed technique can successfully prevent surface collapse during longwall mining under thick unconsolidated layers.