摘要
回采动压和采空区悬顶引起的高静压能够通过关键岩层较为完整地传递到采动大巷,引起动载和静载叠加,造成采动大巷的围岩结构失稳大变形。为减小采动大巷的变形,提出并实施顶板定向压裂应力转移保护采动大巷的方法。该方法通过切断基本顶阻断动压和切断悬顶降低静压的方式,解决大巷受静压和动压双重影响致使巷道围岩结构失稳大变形问题。通过施加动载应力波模拟分析动压对巷道变形的影响规律,认为偏应力和有效应力的增加是动压致使巷道变形的主要原因,并给出最优压裂位置参数。在顾北煤矿13321工作面进行顶板定向压裂工业试验,顶板定向压裂水压力为20~35 MPa,压裂半小时内,裂缝扩展范围半径超过10 m,压裂裂缝连通范围的平均半径达到20 m,贯通范围的最大半径可达到40 m。顶板定向压裂成功地阻断了采动应力和采空区高应力向采动大巷的传播,回采末期停采前微震事件数降低了77%,动压影响范围减少了约200 m,降低了64%,底板胶带机巷两帮移近量减少86%,顶底板移近量减少93%。顶板压裂应力转移保护大巷的方法可以有效减少采动大巷变形。
The dynamic pressure caused by mining and the high static pressure caused by the hanging roof of the goaf can be transmitted to the mining roadway through main roof,causing the superposition of dynamic and static loads,resulting in the instability and large deformation of the surrounding rock structure of the mining roadway.To reduce the deformation of the mining roadway,a method of stress transfer to protect mining roadway by roof directional hydraulic fracturing was proposed and imple-mented.This method solves the problem of instability and large deformation of the surrounding rock structure of the roadway caused by the dual effects of static and dynamic pressure by cutting off the main roof to block dynamic pressure and cutting off the hanging roof to reduce static pressure.By ap-plying dynamic load stress waves,the influence of dynamic pressure on roadway deformation was si-mulated,and it was found that the increase in deviatoric stress and effective stress was the main cause of roadway deformation caused by dynamic pressure.The optimal hydraulic fracturing location parameters were given.An industrial test of directional hydraulic fracturing of the roof was conducted at the 13321 working face of Gubei Coal Mine.The water pressure of the directional hydraulic fracturing of the roof was between 20 MPa and 35 MPa.Within half an hour of hydraulic fracturing,the radius of crack propagation exceeded 10 m,the average radius of crack reached 20 m,and the maximum radius could reach 40 m.The directional hydraulic fracturing of the roof successfully blocked the propagation of mining stress and high stress in the goaf towards the mining roadway.The number of microseismic events before the end of mining was reduced by 77%,the impact range of dynamic pressure was reduced by about 200 m,a decrease of 64%,the movement of the two sides of roadway was reduced by 86%,and the movement of the roof and floor was reduced by 93%.The method of stress transfer to protect mining roadway by roof directional hydraulic fracturing can effectively reduce the deformation of the mining roadway.
作者
黄炳香
邵鲁英
赵兴龙
李浩泽
陈树亮
HUANG Bingxiang;SHAO Luying;ZHAO Xinglong;LI Haoze;CHEN Shuliang(State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Low-Carbon Energy and Power Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2023年第5期991-1002,共12页
Journal of Mining & Safety Engineering
基金
国家重点研发计划项目(2021YFC2902102)。
关键词
坚硬顶板
采动大巷
水压致裂
裂缝扩展
应力转移
hard roof
mining roadway
hydraulic fracturing
fracture propagation
stress transfer
