含水溶洞的存在使得煤层覆岩移动规律具有特殊性.为了研究含水溶洞对煤层覆岩移动的影响,以贵州松南煤矿作为工程背景,利用FLAC3D进行数值模拟研究,对比分析溶洞有无含水作用下煤层覆岩移动规律.研究发现:随着采煤工作面的推进,含水溶洞围岩裂隙和煤层顶板裂隙不断扩展,当工作面推进至与溶洞水平距离小于10 m时,溶洞围岩裂隙和顶板裂隙贯通,形成导水裂隙;含水溶洞煤层开采情况下,溶洞围岩变形下沉量相较于无水情况增加了37.24％,随着推进距离的增加,溶洞靠近采空区侧底角出现明显的下沉现象,溶洞右帮出现向内挤压现象,溶洞围岩和煤层顶板应力集中区和破坏区逐渐贯通;相比于无水情况,覆岩运移在含水条件下得到加强,其中最大曲率增大了0.88 mm/m2、最大水平变形增大了1.81 mm/m.建议该矿采煤工作面与溶洞水平距离需大于10 m.
Abstract
Water-bearing karst caves makes the movement law of coal seam overburden special.In order to study the effect of water-bearing karst cave on the movement of coal bed overburden,Guizhou Songnan Coal Mine was took as the engineering background,FLAC3D was used to carry out numerical simulation research,and comparatively analyze the movement law of overlying rock of coal seam with or without water-bearing karst cave.The research show as follows.With the advance of the coal mining face,the cracks in the surrounding rock of the water-bearing karst cave and the cracks in the coal seam roof continue to expand.When the horizontal dis-tance between the working face and the karst cave is less than 10 m,the cracks in the surrounding rock of the karst cave and the cracks in the roof are connected to form water-conducting cracks.In the case of water-bearing karst cave coal seam mining,the deformation and subsidence of the surrounding rock of the karst cave increased by 37.24％compared with the case without water.With the increase of the advancing distance,the karst cave near the bottom corner of the goaf appeared obvious sinking phenomenon,the right side of the karst cave appeared inward extrusion phenomenon,and the stress concentration area and failure area of the surrounding rock of the karst cave and the roof of the coal seam gradually penetrated.Compared with the water-free condition,the overburden migration is strengthened under the water-bearing condition,in which the maximum curvature increases by 0.88 mm/m2 and the maximum horizon-tal deformation increases by 1.81 mm/m.It suggests that the horizontal distance between the coal mining face and the karst cave should be more than 10 m.
关键词
含水溶洞/覆岩移动/数值模拟/流固耦合/裂隙演化
Key words
water-bearing karst cave/overlying rock movement/numerical simulation/fluid-solid coupling/fracture evolution
维普
万方数据