摘要
为了解决采空区坚硬顶板垮落不完全导致回采巷道上方出现倾覆力矩的危害以及控制相邻巷道围岩失稳变形量过大的难题,采用定向水力压裂超前切顶护巷技术,在凌志达煤业15501工作面采用水力压裂技术进行现场试验,通过理论分析、UDEC数值模拟和现场监测等多种手段对水力压裂效果进行综合分析。结果表明:采用切顶长度为28.28 m,钻孔角度为30°+45°+90°联合水力压裂方案水力压裂效果最明显,该方案实施后,尾端支架的工作阻力减小50%左右,说明周期来压时对支架产生的压力明显降低;水力压裂后钻孔内裂缝数量较多,每段压裂都有数条开裂裂缝,有竖向、环向的、有呈现孔壁破碎的,说明水力压裂效果明显;切顶后被保护巷道顶底以及两帮累计移近量控制在355 mm和310 mm左右,且被保护巷道变形最大范围段内其顶底板及两帮移近量增长率很小,说明切顶减弱或消除了采空区上方坚硬顶板的悬臂结构,改变了被保护巷道的应力赋存环境和稳定性机理,达到了水力压裂切顶护巷的目的。
In order to solve the problem of incomplete collapse of the hard roof in the mining area leading to the hazard of overturning moment above the back mining lane and the problem of controlling the excessive amount of instability and deformation of the adjacent lane surrounding rocks,the directional hydraulic fracturing overtopping cutting and protecting lane technology is adopted,and hydraulic fracturing technology is used in the field test at the 15501 working face of Lingzida coal industry,and the hydraulic fracturing is analyzed by various means such as theoretical analysis,UDEC numerical simulation and field monitoring.The results show that:the most obvious effect of hydraulic fracturing is achieved by using the combined hydraulic fracturing scheme with a top-cutting length of28.28 m and a drilling angle of 30° +45° +90°,and the working resistance of the tail-end bracket is reduced by about 50% after the implementation of this scheme,which indicates that the pressure on the bracket is significantly reduced when the pressure comes from the cycle.After cutting the top of the protected roadway top and bottom as well as the cumulative displacement of the two gangs is controlled at about 355 mm and 310 mm,and the growth rate of the top and bottom plates and the two gangs in the maximum range of the protected roadway deformation was very small,indicating that the top cutting weakened or eliminated the cantilever structure of the hard top plate above the mining area,changed the stress environment and stability mechanism of the protected roadway,and achieved the purpose of hydraulic fracture cutting off the protected roadway.
作者
许晋斌
XU Jinbin(Shanxi Lingzhida Coal Industry Co.,Ltd.,Changzhi 046606,China)
出处
《煤炭技术》
CAS
北大核心
2023年第7期50-56,共7页
Coal Technology
关键词
水力压裂
坚硬顶板
切顶护巷
围岩失稳
hydraulic fracturing
hard roof
cut roof protection roadway
surrounding rock destabilization
