State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine, Anhui University ofScience & Technology
School of Mining Engineering, Anhui University of Science &Technology
Mining Engineering Post-Doctoral Flow Station, Anhui University ofScience & Technology
Post-Doctoral Research Station,Huainan Mining Industry (Group) Co Ltd

为研究深部煤层综采工作面采动卸压覆岩裂隙演化规律,以芦岭煤矿Ⅲ1022综采工作面为工程背景,采用光频域反射技术(OFDR)分析相似模拟试验采动覆岩裂隙演化全过程,结合现场瓦斯抽采情况及光纤监测结果,对采场裂隙时空演化规律进行研究。研究结果表明:工作面回采过程中,采空区覆岩水平方向光纤拉应变曲线呈左、右两峰,两峰间距表征覆岩实际垮落宽度,两峰峰值处为工作面两侧采动破断线。垂直方向受超前支承压力影响,工作面前方出现压应力集中区域,光纤压应变曲线呈台阶递减状态,采空区顶底板皆出现拉应变凸峰。工作面上隅角风排瓦斯浓度、1#定向钻场拦截孔、5#地面井的卸压瓦斯抽采情况,反演了工作面采动裂隙的演化特征,结合现场光纤监测试验,判断采场覆岩裂隙带发育高度为77.5m,覆岩裂隙发育层位已至8、9煤层。研究结果为工作面开采工艺设计、邻近层瓦斯运移、抽采的钻孔设计、瓦斯治理等提供理论基础,对矿井安全高效生产起明显促进作用。

To investigate the evolution law of fractures in the overburden during pressure relief of fully mechanized mining faces in deep coal seams, similar simulation tests were conducted on the Ⅲ1022 fully mechanized mining face of Luling Coal Mine by adopting the optical frequency domain reflection (OFDR) technology. The resulting data allowed for analysis on the entire process of fracture evolution in the overburden. In this study, the temporal and spatial evolutions of fractures in the stope were explored on the basis of the on-site gas drainage data and the optical fiber monitoring results. The findings demonstratethat during the mining process of the working face, the tensile strain curve of optical fibers in the horizon- tal direction of the overburden in the goaf exhibits “left and right peaks”. The distance between two peaks represents the actual collapse width of the overburden, and the peak values of them correspond to the min- ing fracture lines on both sides of the working face. Meanwhile, the advanced abutment pressure exerts an influence in the vertical direction, leading to the concentration of compressive stress in front of the working face. The compressive strain curve of optical fibers tends to decline stepwise, with tensile strain peaks appearing in the roof and floor of the goaf. Furthermore, the evolution characteristics of mining-in- duced fractures in the working face were deduced in accordance with the gas concentration data at the up- per corner of the working face, the pressure relief gas drainage data from the 1 # interception borehole of the directional drilling field, and the pressure relief gas drainage data from the 5 # surface well. Besides, according to on-site optical fiber monitoring results, the fracture zone in the stope has developed to a height of 77.5 m, and the fracture layer of the overburden has reached the 8 # and 9 # coal seams. The re- search results are expected to provide a theoretical foundation for the design of mining technology in the working face, gas migration in adjacent layers, arrangement of drainage boreholes, and gas control, which is of great significance for promoting safe and efficient production in coal mines.

安徽理工大学2022年研究生创新基金项目(2022CX2032);国家自然科学基金项目(52004005);安徽省博士后基金项目(2021B513);安徽省高校协同创新项目(GXXT-2021-075);安徽省“省特支计划”的领军人才项目(T000508);安徽省教育厅研究生学术创新项目(2022xscx080)