基于颗粒流的浅埋双煤层斜交开采地表裂缝发育特征

Ground surface fracture development characteristics of shallow double coal seam staggered mining based on particle flow

陕北浅埋煤层开采引起地面塌陷严重影响了矿区生态环境,与浅埋单煤层开采相比,浅埋双煤层开采所导致的覆岩破坏、裂缝发育更为复杂。以柠条塔煤矿N1206和N1114典型工作面为研究对象,采用颗粒流方法对浅埋双煤层斜交开采的过程及其所致地表裂缝发育特征进行了模拟研究。研究结果表明:浅埋双煤层斜交开采煤柱所在区域的上行和下行裂隙密集发育;各工作面采毕地表下沉曲线呈现宽缓的“W”型;1^-2煤采毕与2^-2煤采毕裂缝发育速率比值为1:3~1:2,地表最大下沉量比值为1:7;开切眼及终采线位置附近裂缝密集且会导通至地表;地表最大下沉量位于工作面开切眼位置附近,地表最大水平正向位移位于工作面开切眼位置附近,左侧工作面采毕最大负向位移位于工作面终采线位置,右侧工作面采毕最大负向位移位于1^-2煤右侧工作面靠近终采线位置。研究结果可为浅埋双煤层开采的相关研究与工程实践提供理论参考与实际借鉴。

The surface subsidence caused by shallow seam mining in northern Shaanxi has seriously affected the ecological environment of the mining area. Compared with shallow single seam mining,the overburden damage and fracture development caused by shallow double seam mining are more complex. Taking N1206 and N1114 typical working faces in Ningtiaota Coal Mine as the research object,this paper simulated the process of staggered mining in shallow double seam and the development of its ground fissures characteristics by applying the particle flow method. The results showed that there were multiples upward and downward cracks in the area where the shallow double seam staggered mining pillars located, and the surface subsidence curve of each working face showed a gentle "W" type.The ratio of crack growth rate of 1^-2coal mining and 2 ^-2 coal mining was 1:3-1:2 and the ratio of maximum subsidence of surface was 1:7. The cracks near the cut-off and stopping line were dense and they will continuous to extend until surface. The maximum subsidence was near the cut-in position of the working face and the maximum horizontal positive displacement of the surface was near the cut-in position of the working face. Meanwhile, the maximum negative displacement of the left working face was near the stop-in line of the working face,and the maximum negative displacement of the right working face was near the stop-in line of the 1 ^-2coal face. This study can provide theoretical reference and practical significance for the related research and engineering practice of green mining in shallow double seam.