采动影响下逆断层阶段性活化诱冲机制

Mechanics of rock-burst induced by thrust fault phased activation under mining disturbance

为了探明采动影响下逆断层诱冲机制,结合现场数据、理论推导以及数值模拟方法,综合分析了采动影响下逆断层活化过程,从动静载扰动的角度进一步分析了采动影响下逆断层诱冲机制。采动影响下逆断层活化为阶段性过程,通过滑移倾向性指标Ts以及滑移量的分析可以将该过程分为3个不同的阶段。研究表明:逆断层高位区域Ts值及滑移量较大,为断层面活化过程中的危险区域,且断层面活化危险程度受断层倾角以及工作面到断层距离l的影响。逆断层的存在改变了井下开采结构,造成了工作面应力状态的改变,且逆断层阶段性活化过程中会不同程度的释放能量。数值模拟结果表明:采动影响下逆断层诱冲机制主要由动静载2方面引起:静载扰动方面,逆断层倾角的减小会造成工作面超前支承压力集中系数的增大,加大了冲击地压危险性;另一方面,逆断层阶段性活化过程中释放的能量以动载的方式对工作面造成冲击,该能量可以用地震矩M0来表征。M0与工作面到断层距离l之间存在指数相关性,该相关性中的p,q值可以用来表征工作面在回采过程中逆断层能量积累程度。p值反映开采后期断层面能量积累程度、q值反映开采初期断层面能量积累程度。p,q值越大表明断层能量积累程度越高,断层发生滑移错动后释放能量越高,对工作面冲击越大,越容易诱发冲击地压的发生。分析发现:p值随着断层倾角的减小而增大,q值随着倾角的增大而增大。

In order to ascertain the impact of mining disturbance on the complex mechanical interaction mechanism of thrust fault on rock-burst,this paper combines the field data,theoretical derivation and numerical simulation methods to comprehensively analyze the activation process of thrust fault under mining disturbance.From the perspective of dynamic-static loading disturbance,the mechanism of rock-burst induced by thrust fault under the influence of mining was further analyzed.The activation of the thrust fault under the influence of mining is a staged process,and the process can be quantitatively divided into three stages through the slip tendency index Ts:quasi-static,activation,and slippage.The high level fault area is a dangerous area during the activation of the fault,and the degree of danger of the fault activation is affected by the fault dip angle and the distance from the working surface to the fault.The research results show that the mechanism of rock-burst induced by thrust fault under the influence of mining is mainly caused by dynamic and static loading.On the one hand,the decrease of the fault dip angle will cause the concentration factor of the leading support pressure on the working face to increase,increasing the danger of rock-burst.On the other hand,the energy released during the phased fault activation process can be characterized by the seismic moment M0.There is an exponential correlation between M0 and the distance l from the working face to the fault.The p and q values in this correlation can be used to characterize the degree of seismic moment released of the thrust fault during the mining process.The p value reflects the energy released level of the fault at the later stage of mining,and the q value reflects the energy released level of the fault at the early stage of mining.Larger values of p and q indicate a higher degree of fault energy released.The higher the energy released after the fault slips,the greater the impact on the working surface,and the easier it is to induce the occurrence of rock-burst.The analysis found that the p value decreases with the increase of the fault dip angle,and the q value increases with the increase of the fault dip angle.