宁夏羊场湾煤矿浅埋煤层开采地面塌陷发育规律及形成机理

以宁夏羊场湾煤矿Y110207工作面为研究对象,采用无人机遥感技术、野外调查与有限差分软件模拟方法研究浅埋煤层开采的地面塌陷类型、发育规律及其形成机理。(1)浅埋煤层开采地面塌陷以地表裂缝发育为主,地表破坏严重。(2)平行切眼裂缝间隔性出现,展布于整个工作面内,间隔距离为10～120m,局部裂缝形成错台高度约为15cm。平行顺槽裂缝为拉张型裂缝,发育在顺槽至外围一定范围。(3)采煤活动导致地下形成采空区,上覆岩层发生移动破坏,破坏区分为剪切破坏区、拉张破坏区及剪-拉破坏区,分别对压应力区、拉应力区和压-拉转化区。(4)当应力扰动传递至地表,应力值超过覆盖层抗拉强度时地表产生裂缝。随着工作面推进,覆岩内部裂缝带上行裂缝与地表下行裂缝贯通,形成错台。研究成果丰富了该区浅埋煤层的地面塌陷理论知识,为地面塌陷防治提供了理论依据。

A study of the development regularity and formation mechanism of ground subsidence in shallow coal seam mining of Yangchangwan coal mine, Ningxia

The mechanism of ground subsidence induced by coal mining is an important theoretical basis for the prevention and is also one of the hotspots in the study of geological environment. Subsidence type, features and the mechanism were studied by methods of the UAV remote sensing technology, field observation and numerical simulation software on the Y110207 working face in Yangchangwan coal mine, Ningxia. The results show that, during shallow coal seam mining, cracks and surface collapses are developed, which cause ground surface destruction. In the working face, the parallel cutting cracks are distributed with an interval distance between 10~120m. The parallel channel fracture is a tensile fracture, which is developed in a certain range from the trough to the periphery. The coal mining activities lead to the move and destruction of the overlying strata. The damage can be divides into three types, i.e., shear failure zone, tensile failure zone and shear-tensile failure zone, corresponding to compressive stress region, tensile stress zone and compression tensile transition zone. When the stress is more than the tensile strength of the covering layer transferring to the surface, the cracks will occur. With the advancing of the working face, the water flowing fracture zone will develop to the surface. After that cracks will perforate and the staggered platform will emerge. It enriches the theoretical knowledge of ground subsidence in shallow coal seam and provides a theoretical for the prevention.