葫芦素煤矿采动覆岩离层发育规律研究

Study on the Development Law of Mining-Induced Overburden Bed Separation in Hulusu Coal Mine

摘要: 为揭示深埋厚煤层开采条件下覆岩离层的易发层位、演化过程及控制机制，以葫芦素煤矿某工作面为研究对象，综合采用传递岩梁理论和UDEC离散元模拟方法，并利用呼吉尔特矿区5个生产煤矿的导水裂隙带裂采比资料进行区域经验校核。结果表明：第11层粉砂岩、第13层细砂岩、第15层粉砂岩、第17层粉砂岩和第19层粉砂岩为主要潜在离层层位。矿区平均裂采比为23.76，对应4 m采厚条件下导水裂隙带经验高度约95.04 m；UDEC模拟得到的采动裂隙–离层机械影响上限约120 m，较经验值高26.26%，说明力学模型对破坏影响范围的预测具有一定上限性，不能直接等同于稳定导水通道高度。高位局部离层最高可发育至约202 m，但与下部裂隙区并非完全贯通。离层演化经历低位缓慢增长、中部快速上移和高位受限稳定三个阶段，最大开度由推进120 m时的2.53 m减小至推进340 m时的0.69 m，走向长度最大约142 m。采厚由4 m增至6 m和9 m后，离层上移提前，但最高层位仍稳定在202~203 m；硬型和软硬互层型顶板条件下高位离层可发育至约202 m，软型顶板条件下约120 m。研究表明，采厚主要影响离层发育速率和开度，高位厚硬层的位置及软硬岩层组合控制最高离层层位，可为类似地质条件下的离层水害判识提供依据。

Abstract: To reveal the prone horizons, evolutionary process, and controlling mechanisms of overburden bed separation under deep-buried thick-seam mining conditions, a working face in the Hulusu Coal Mine was selected as the study area. The transfer rock-beam theory and UDEC discrete-element modelling were employed, and regional empirical validation was conducted using data on the height-to-mining-height ratios of the water-conducting fractured zone from five producing coal mines in the Hujierte Mining Area. The results indicate that the 11th siltstone layer, 13th fine sandstone layer, 15th siltstone layer, 17th siltstone layer, and 19th siltstone layer are the main potential bed-separation horizons. The average height-to-mining-height ratio in the mining area is 23.76, corresponding to an empirical water-conducting fractured-zone height of approximately 95.04 m for a mining height of 4 m. The UDEC simulation yields an upper limit of approximately 120 m for the mechanically affected mining-induced fracture-separation zone, which is 26.26% higher than the empirical value. This indicates that the mechanical model provides an upper-bound estimate of the affected failure range and that the simulated height cannot be directly equated with the height of a stable water-conducting pathway. The highest isolated bed separation develops to approximately 202 m above the coal seam, but it is not fully connected to the lower fractured zone. Bed-separation evolution proceeds through three stages: slow growth at low levels, rapid upward migration at intermediate levels, and constrained stabilization at high levels. The maximum opening decreases from 2.53 m at an advance distance of 120 m to 0.69 m at 340 m, while the maximum strike length reaches approximately 142 m. When the mining height increases from 4 m to 6 m and 9 m, upward migration of bed separation occurs earlier, whereas the maximum development horizon remains stable at approximately 202~203 m. Under hard-roof and interbedded soft–hard roof conditions, high-level bed separation can develop to approximately 202 m, whereas under soft-roof conditions, the maximum height is approximately 120 m. These results demonstrate that mining height primarily affects the development rate and opening of bed separation, whereas the position of high-level thick and hard strata and the assemblage of soft and hard rock layers control the maximum bed-separation horizon. The findings may provide a reference for identifying bed-separation water hazards under similar geological conditions.