厚松散含水层失水沉降相似模拟实验研究

目前缺乏对厚松散含水层地质采矿条件下覆岩破断及变形规律的深入研究。以淮南矿区潘四东煤矿11111工作面为工程背景,构建相似材料模型,采用数字摄影测量提取位移法记录模型开挖过程中覆岩破断过程及覆岩变形情况。分析了含水层失水沉降原因:覆岩在W型剪切应力拱作用下形成2条纵向的主导水裂隙带,导水裂隙带的进一步发育引起含水层失水固结,在厚松散层重力作用下进一步压实,随着覆岩破断运动的加剧,在弯曲带和覆岩共同挤压下形成О型剪切应力拱,压缩薄层空间,导致地表下沉量增大。分析了失水状态下覆岩损伤情况:工作面开采工作完成且覆岩达到稳态后,前垮落角为57°,后垮落角为62°,导水裂隙带高度为63 m,开切眼及终采线上方覆岩在应力集中作用下断裂,产生纵向裂隙,开切眼及终采线上方垮落带区域内覆岩产生横向离层裂隙,纵向裂隙和横向离层裂隙加剧了覆岩与含水层间的水力联系。给出了失水状态下覆岩动态运动规律:随着开采工作面的推进,各观测线覆岩下沉量逐渐增大,接近开采工作面的观测线覆岩下沉量最大,工作面上方覆岩的观测线下沉量曲线走势基本类似且跳变一致,含水层上方的观测线下沉量曲线走势基本吻合且跳变同步,工作面上方与含水层上方的观测线下沉量跳变异步,表明含水层对覆岩移动变形具有重要作用。

Similar simulation experiment of water loss and settlement in thick loose aquifer

The in-depth research on the breaking and deformation law of overburden rock under the geological and mining conditions of thick loose aquifer are lacking at present.Taking 11111 working face of Pansidong Coal Mine in Huainan mining area as the engineering background,the similar material model is constructed,and the digital photogrammetry extraction displacement method is used to record the overburden rock breaking process and overburden rock deformation during the model roadway heading.The causes of water loss and settlement of aquifer are analyzed.The overburden rocks form two main longitudinal diversion fissure zones under the action of W-type shear stress arch.The further development of the diversion fissure zone causes water loss and consolidation of the aquifer,and the aquifer is further compacted under the action of gravity of the thick loose layer.With the intensification of the overburden rock breaking movement,Оtype shear stress arch is formed under the joint extrusion of bending zone and overburden rock,which compresses the thin space and leads to the large amount of surface subsidence.The damage of overburden rock under water loss condition is analyzed.After the roadway heading work of the working face is completed and the overburden rock reaches a steady state,the front caving angle is 57°,the rear caving angle is 62°,and the height of the diversion fissure zone is 63 m.Under the action of stress concentration,the overburden rock above the open-cut hole and the stop-mining line is broken to produce longitudinal fissure,and the overburden rock in the area of the collapse zone above the open-cut hole and the stop-mining line produces lateral separation fissure.The longitudinal fissures and lateral separation fissures intensify the hydraulic connection between overburden rock and the aquifer.The dynamic movement law of overburden rock under water loss state is given.With the advance of mining face,the overburden settlement of each observation line increases gradually,and the overburden settlement of the observation line close to the working face is the largest.The trend of the subsidence curves of the observation lines in the overburden rock above the working face is basically similar,and the jump of the subsidence curves is consistent.The trend of the subsidence curves of the observation lines above the aquifer is basically consistent,and the jump of the subsidence curves is synchronous.The jump of the subsidence curves of observation lines in the overburden rock above the working face and the one of the observation lines above the aquifer are asynchronous,indicating that the aquifer plays an important role in the movement and deformation of the overburden rock.