摘要
针对煤层坚硬顶板难垮落造成的沿空留巷围岩控制难题,以某矿111工作面为工程背景,在预留巷道顶板进行了水力分段压裂切顶卸压。首先建立了理论力学模型计算分析坚硬顶板垮落影响因素;其次采用数值模拟对比了不同分段点间距及钻孔倾角对切顶效果影响;最后在现场进行了水力分段压裂试验并采用十字布点法进行效果验证。研究结果表明,水力分段压裂钻孔倾角及分段压裂点应力状态决定顶板能否及时垮落,以此进行数值模拟分析,最终确定分段压裂点间距为3 m、切顶钻孔倾角为45°时顶板弱化效果较好。现场试验巷道底鼓量最大为210 mm,顶板下沉量最大为121 mm,两帮移近量最大分别为42 mm和61 mm。该技术避免了工作面坚硬顶板来压对沿空留巷的冲击,有效解决了沿空留巷围岩控制难题,为解决沿空留巷类似问题提供参考。
Aiming at the problem of controlling the surrounding rock of gob-side entry retaining caused by the difficult collapse of the hard roof of the coal seam,taking the 111 working face of a mine as the engineering background, the hydraulic staged fracturing roof cutting pressure relief is carried out on the roof of the retaining roadway. Firstly, a theoretical mechanical model is established to calculate and analyze the influencing factors of the hard roof collapse;then, the influence of different segmentation point spacing and borehole inclination angle on the roof cutting effect is compared by numerical simulation;finally, the hydraulic staged fracturing test is carried out on the spot and the effect is verified by the cross point method. The results show that the dip angle of the hydraulic staged fracturing borehole and the stress state of the staged fracturing point determine whether the roof can collapse in time, so the numerical simulation analysis is carried out, and the roof weakening effect is better when the spacing of the staged fracturing points is 3 m and the inclination angle of the roof cutting borehole is 45°. The maximum deformation of the roadway bottom in the field test is 210 mm, and the maximum amount of roof subsidence is 121 mm. The maximum approach of the two gangs is 42 mm and 61 mm respectively. This technology avoids the impact of the hard roof of the working face in gob-side entry retaining engineering, effectively solves the problem of surrounding rock control and provides a reference for solving similar problems in gob-side entry retaining engineering.
作者
李明轩
刘勇
王永洁
高龙
刘永强
王滨
雷顺
LI Mingxuan;LIU Yong;WANG Yongjie;GAO Long;LIU Yongqiang;WANG Bin;LEI Shun(Tiandi(Yulin)Mining Engineering Technology Co.,Ltd.,Yulin 719000,China;Mining Research Branch,China Coal Research Institute,Beijing 100013,China;Tiandi Science&Technology Co.,Ltd.,Beijing 100013,China;Shaanxi Yulin Daliangwan Coal Mine Co.,Ltd.,Yulin 719000,China;Shaanxi Yidong Mining Co.,Ltd.,Shenmu 719300,China)
出处
《中国矿业》
2023年第12期153-160,共8页
China Mining Magazine
基金
天地科技股份有限公司开采设计事业部资助项目资助(编号:TDKC-2022-QN-05)。
关键词
坚硬顶板
水力压裂
围岩控制
数值模拟
沿空留巷
hard roof
hydraulic fracturing
surrounding rock control
numerical simulation
gob-side entry retaining