Rock burst prevention technology in multi-roadway intersection area of hard roof strong impact working face
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摘要: 为保障坚硬顶板条件下强冲击工作面回采过程中多巷交叉区域安全性,以陕西彬长胡家河矿业有限公司401111工作面回采末期为工程背景,采用理论分析、现场监测的方法对末采期间工作面冲击危险区域进行等级划分,分析了导致冲击危险性升高的动静载荷影响因素,并对比了正常回采期间与末采期间动静载荷监测情况。结果表明:401111工作面开采煤层具有强冲击倾向性,在坚硬顶板条件下,本工作面采空区、相邻采空区和多巷交叉区域提供了静载荷,采空区上覆坚硬顶板悬顶和垮断及多巷交叉区域弹性能瞬时释放提供了动载荷,动静载荷共同作用导致401111工作面回采末期冲击危险性升高,且回风巷侧多巷交叉区域冲击危险性高于运输巷侧。采用冲击地压分源防治思想:针对上覆坚硬顶板,利用顶板预裂爆破技术,缩短顶板垮落步距,降低顶板大面积悬顶和垮断产生的动载扰动影响;针对巷道帮部和底板,采用大孔径钻孔卸压,减少静载荷积聚,降低围岩受载程度。同时对巷道顶板实施锚杆+钢带网与锚索联合支护方式,对巷道帮部采用锚索+钢筋梯网支护方式,提高围岩抗冲击能力。采用基于卸压和联合支护的防冲技术后,微震事件大幅降低,表明煤岩体破裂程度较低,完整性较好,保证了工作面回采安全性。Abstract: In order to ensure the safety of multi-roadway crossing area in the mining process of strong impact working face under hard roof, the end mining of 401111 working face of Shaanxi Binchang Hujiahe Mining Co., Ltd. is taken as the engineering background. The method of theoretical analysis and field monitoring is used to classify the rock burst hazard area of the working face during the end mining period. Moreover, the dynamic and static load influencing factors that lead to the increase of rock burst hazard are analyzed. The dynamic and static load monitoring situation during normal mining and the end mining are compared. The results show that the 401111 working face mining coal seam has strong rock burst tendency. Under the condition of hard roof, the static load is provided by the working face goaf, adjacent goaf and multi-roadway intersection area. The dynamic load is provided by the instantaneous release of elastic energy in the overlying hard roof overhanging and collapsed and multi-roadway intersection areas in the goaf. The joint action of dynamic and static loads leads to an increase in the rock burst hazard of the 401111 working face at the end of mining. And the rock burst hazard in the intersection area of the return air roadway is higher than that of the transport roadway side. The idea of separate source prevention and control of rock burst is adopted. For the overlying hard roof, the roof pre-split blasting technology is used to shorten the roof collapse step. And the dynamic load disturbance caused by the large-area overhang and collapse of the roof is reduced. For the roadway side and floor, large-diameter drilling is used to relieve pressure so as to reduce the accumulation of static load and the degree of load on the surrounding rock. At the same time, the roof of the roadway is supported by bolt+steel belt mesh and anchor cable. The side of the roadway is supported by anchor cable+steel ladder mesh so as to improve the rock burst resistance of surrounding rock. After using the rock burst prevention technology based on pressure relief and joint support, the micro-seismic events are greatly reduced. The result indicates that the coal and rock mass fracture degree is low and the integrity is good, and the safe mining of the working face is ensured.
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表 1 4号煤层冲击倾向性鉴定结果
Table 1. Rock burst tendency evaluation results of No.4 coal seam
煤层 动态破坏
时间/ms弹性能
指数冲击能量
指数抗压强度/
MPa冲击倾向性 上分层 39.80 6.49 7.73 24.27 强冲击倾向性 下分层 34.40 4.45 12.57 24.35 强冲击倾向性 表 2 冲击危险等级划分标准
Table 2. Classification standard of rock burst hazard level
冲击危险指数α 冲击危险等级 α≤7 无冲击危险 7<α≤14 弱冲击危险 14<α≤21 中等冲击危险 α>21 强冲击危险 表 3 401111工作面回采末期巷道冲击危险区域等级划分
Table 3. Classification of rock burst hazard area level of roadway at the end of mining in 401111 working face
位置 冲击危险指数 集中动静载荷
影响因素冲击危险等级 运输巷及运输措施巷 9 周期来压、巷道交叉布局 弱冲击危险 回风巷、回风联络巷及
回风措施巷24 周期来压、巷道交叉布局、
相邻采空区、煤柱宽度强冲击危险 -
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