Study on the failure mechanism and control technology of surrounding rock of soft rock roadway near fault
XIE Xiaoping,WU Gang,YU Rui,LIU Xiaoning
基于某煤矿断层附近软岩巷道围岩变形破坏严重的问题,采用试验测试、理论分析和数值模拟相结合的方法,分析了原回采巷道支护方案及其效果,研究了该煤矿断层附近巷道围岩破碎区范围、构造应力规律及泥岩风化和水理共同作用的崩解软化特征,研究了断层附近软岩巷道围岩变形控制对策,提出了“锚带网喷+中空注浆锚索”联合支护技术方案。根据现场2408工作面回风巷的实际条件,通过钻孔录像对新开掘巷道围岩内部进行观察得出:巷道围岩1~3 m较为破碎,4~5 m破碎程度较小,但是也存在一定得裂隙,矿井断层带附近软岩巷道围岩控制应充分考虑对破碎区围岩的加固;通过地应力测量结果可知:该煤矿井下断层构造应力以水平应力为主,即矿井巷道围岩控制应充分考虑水平应力的影响;数值模拟分析结果显示巷道采用原有支护方案时,巷道左帮、右帮、顶板、底板最大变形量分别为-109、-160、-133、-112 mm,巷道采用优化支护方案时,巷道左帮、右帮、顶板、底板最大巷道变形量为-66、-65、-49、-86 mm,即巷道采用优化支护技术方案后,围岩变形量明显降低,进而确定了回采巷道优化联合支护的技术参数。2408回风巷掘进40 d后,巷道围岩逐渐趋于稳定,两帮的相对移近量和顶板下沉量均小于50 mm,相对于采用原支护方案围岩变形量降低50%以上,巷道围岩变形得到有效控制。
Based on the serious deformation and failure of the surrounding rock of a soft rock roadway near a fault in a coal mine,a combination of experimental testing,theoretical analysis and numerical simulation was used to analyze the original mining roadway support plan and its effect,and the coal mine roadway surrounding rock broken zone near fault was studied.The range of rock fragmentation zone,the law of tectonic stress,and the disintegration and softening characteristics of mudstone weathering and water were studied.The control measures for the deformation of the soft rock roadway near the fault were studied,and "the anchor belt mesh spray + hollow grouting anchor cable" combined supporting technology solutions were proposed.According to the actual conditions of the return airway in No.2408 working face,this paper observes the surrounding rock of the newly excavated roadway through drilling videos.It is concluded that the surrounding rock of the roadway is relatively broken between 1~3 m,and less broken between 4~5 m,but there are also some small fissures.The surrounding rock control of the soft rock roadway near the fault zone of the mine should fully consider the reinforcement of the surrounding rock in the broken zone; The results of in-situ stress measurement show that the tectonic stress of the fault in the mine is mainly horizontal stress,that is,the influence of horizontal stress should be fully considered in the control of surrounding rock of mine roadway.Numerical simulation analysis shows that when the original support scheme is adopted for the roadway,the maximum deformation of the left side,right side,roof and floor of the roadway is -109,-160,-133,-112 mm respectively; when the optimized support scheme is adopted for the roadway,the maximum roadway deformations of the left,right,roof and floor of the roadway are -66,-65,-49,-86 mm respectively,that is,the deformation of the surrounding rock is significantly reduced,and the technical parameters of optimized combined support of the mining roadway are determined.Field test results show that the surrounding rock of the roadway gradually stabilized after 40 days of excavation of No.2408 return air roadway,and the relative moving amount and roof subsidence amount of both sides were less than 50 mm.Compared with the deformation of the surrounding rock in the section with the old support,the surrounding rock deformation of the roadway is reduced by more than 50%,and the surrounding rock deformation of the roadway was effectively controlled.
fault; ground stress measurement; roadway support; grouting anchor cable; mine pressure observation
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会