高应力断层构造区巷道冲击破坏特征研究

Research on the features of impact damage in roadways in high stress fault structure areas

断层构造区静动载应力耦合作用加剧了井下断层区围岩冲击危险性,断层构造区巷道围岩应力分布规律及冲击动载响应特征存在显著特殊性。目前对于断层构造区的冲击研究主要集中于工作面采场附近,但对于断层构造区巷道冲击破坏鲜有研究。以陕西某矿深埋高应力断层构造区巷道为工程背景,分析了断层构造区巷道围岩变形破坏力学特征:①断层面存在明显应力阻隔效应,正断层附近存在上盘应力集中区和下盘应力降低区2个特殊应力区。巷道由于断层面影响,巷帮静载集中应力呈现非对称分布特征,远离断层面侧应力集中程度大于靠近断层面侧,该侧巷道围岩冲击破坏危险程度增大。②断层面对于应力波传递产生明显阻隔作用,正断层上盘动载响应大于下盘动载响应,由于巷道两帮应力非对称分布特征,右帮动载响应明显大于左帮。基于上述特征,提出了断层构造区巷道围岩“卸(大直径钻孔卸压)−支(梯次加固成层式吸能防冲支护)”协同防冲控制技术,工程试验结果表明:①巷道围岩采取“卸−支”协同防冲处理措施后,巷道两帮应力集中区往围岩深部转移3~5 m,应力峰值降低18.5%~20.3%,巷道帮部围岩应力集中程度显著降低。②采用“卸−支”协同防冲处理措施前,巷道顶底板及两帮变形量分别为856,334,325,567 mm,巷道围岩变形破坏严重,采用“卸−支”协同防冲处理措施后,巷道围岩变形量降低35.69%~62.03%,巷道围岩稳定性增强。③钻孔煤粉量显著低于临界粉煤量,巷道围岩动力显现降低。

The coupling effect of static and dynamic stress in fault structure areas exacerbates the risk of rock impact in underground fault areas.The stress distribution law and impact dynamic load response features of roadway surrounding rock in fault structure areas have significant peculiarities.At present,research on the impact of fault structures mainly focuses on the vicinity of the working face,but there is little research on the impact damage of roadways in fault structures.Taking the roadway in a deep buried high stress fault structure area of a mine in Shaanxi Province as the engineering background,the mechanical features of deformation and failure of the roadway surrounding rock in the fault structure area are analyzed.①There is a significant stress barrier effect on the fault plane,and there are two special stress zones near the normal fault,namely the stress concentration zone in the hanging wall and the stress reduction zone in the lower wall.Due to the influence of the fault plane,the static load concentration stress of the roadway side shows an asymmetric distribution feature.The stress concentration on the side far from the fault plane is greater than that on the side near the fault plane,and the risk of impact damage to the surrounding rock of the roadway on this side increases.②The fault plane has a significant barrier effect on the transmission of stress waves,and the dynamic load response of the hanging wall of the normal fault is greater than that of the lower wall.Due to the asymmetric distribution of stress on the two sides of the roadway,the dynamic load response of the right side is significantly greater than that of the left side.Based on the above features,a collaborative anti impact control technology of"unloading(large diameter drilling pressure relief)-support(stepped reinforcement into layered energy absorption and anti impact support)"is proposed for the surrounding rock of the fault structure area roadway.The engineering test results show the following points.①After adopting the"unloading support"collaborative anti impact treatment measures for the roadway surrounding rock,the stress concentration areas of the two sides of the roadway are transferred to the deep part of the surrounding rock by 3-5 meters.The stress peak value is reduced by 18.5%-20.3%,and the stress concentration degree of the roadway surrounding rock is significantly reduced.②Before the implementation of the"unloading support"collaborative anti impact treatment measures,the deformation of the roadway roof,floor,and two sides are 856,334,325,and 567 mm,respectively.The deformation and damage of the roadway surrounding rock are severe.After adopting the"unloading support"collaborative treatment measures,the deformation of the roadway surrounding rock decreases by 35.69%-62.03%,and the stability of the roadway surrounding rock is enhanced.③The coal powder content in the borehole is also significantly lower than the critical coal powder content,and the dynamic power of the roadway surrounding rock is reduced.