浅埋厚煤层条带充填保水开采分析研究

我国西北地区浅埋厚煤层开采对地表及潜水层造成严重破坏,而充填开采是减小地表破坏以及实现保水开采的有效途径。为研究浅埋厚煤层条带充填保水开采的安全性,以哈拉沟煤矿为研究对象,建立了“边界煤柱+条带充填体+覆岩”的力学模型,采用相似试验与现场实测相结合的方法,在周期来压步距、地表下沉及台阶裂缝等方面进行对比分析,得出了较为准确的基岩裂缝角及直接顶初次垮落步距,并通过对隔水层的稳定性分析,确定了条带充填开采的充填宽度为38 m,充填间隔为16 m。根据土工试验得到黄土层的相关力学参数,确定了下行裂缝的发育深度。结果表明:条带充填开采引起的下行裂缝未影响到主关键层,有效隔水岩组厚度满足相关规程要求,可实现安全保水开采。

Analysis on Strip-filling in Water Preserved Mining under Shallow Buried Thick Coal Seam

Shallow buried thick coal seam mining caused serious surface subsidence and phreatic water loss in northwest China. Strip filling mining is an effective way to reduce surface damage and achieve water preserved mining. In order to study the safety of strip-filling in water preserved mining under shallow buried thick coal seam, the Halagou coal mine had been chosen to be the research field. The mechanical model of “Boundary pillar + Strip-filling body + Overburden” had been established. The physical simulation and field measurement method were compared and analyzed from the aspect of the periodic weighting step, the maximum surface subsidence and step fissure. The crack angle in the bedrock and first direct roof caving step were obtained. Meanwhile, according to the analysis of the water resisting strata, it can be determined that the filling width of strip-filling was 38 m, and filling interval was 16 m. According to the soil test, the mechanical parameters of the loess layer were obtained, and the development depth of downward crack was determined. Furthermore, the development height of upward crack was also obtained through the numerical simulation. The results demonstrate that the primary key stratum was not affected by the downward crack caused by strip-filling mining, and it meets the requirement of Chinese regulations. Therefore, it can realize the safety of water preserved mining.