采动影响下断层滑移失稳研究

为研究采动影响下活动断层的滑移情况,以抚顺矿区老虎台矿为背景,建立了采动条件下覆岩运动的突变力学模型,确定了断层发生滑动的必要条件;运用UDEC数值模拟软件对工作面开采条件下断层活动进行分析,现场工业性试验对断层活动进行监测和验证。结果表明,断层失稳的必要条件为刚度值k≤1,刚度比随着开采深度的增加而逐渐降低;当弹性段采出厚度大于85 m时,F25断层具备了发生滑动的必要条件,易发生冲击地压。83003工作面开采后,F25断层下盘位移基本不变,上盘位移活动幅度较大,最大位移达到了5~7m;锚索测力计的应力变化与断层活动具有较大的相关性,当锚索测力计数值突变时,表明断层已经活动,锚索测力计数值突变越大,预示冲击地压和矿震能量越大。

Study on the fault slipping under the strong impact of mining activities

In order to research the slipping conditions of active fault under the influence of mining,and predict the occurrence of rock burst more precisely,the present paper would like to Laohutai Coal Mine under Fushun Coal-Mine Group as a case study case.For the research purpose,we have established a mutation mechanical model of rock strata movement under the impact of mining activities so as to identify and determine the necessary condition to prevent the crop-up fault sliding.Also for the aforementioned purpose,we have made an analysis for the fault activity under the mining conditions by using a UDEC numerical simulation software,with the research result being monitored and verified by an industrial test.The research results of the paper prove that the stiffness ratio k ≤ 1 is the necessary condition responsible for the fault instability and the stiffness ratio,which tends to decrease gradually with the increase of the mining depth.If the mining thickness of elastic section is beyond 85 m,the rock burst would happen when all the necessary conditions for the said sliding were to be made ready.Thus,it can be seen from the above said numerical simulation results that if panel 83003 were fully excavated,almost the same is true with the footwall displacement of F25 fault.More serious displacement would happen with the hanging wall and the maximum displacement may reach by the extent between 5 m and 7 m.In addition,the greatest hanging wall displacement would occur due to the fault at a depth of 230 m above the roof of coal seam due to the increased rock interface activity because of the fault.Moreover,some correlations between the anchor cable stress variation and the activity of fault would also be intensified as is shown by the anchor cable dynamometer.More exactly speaking,the greater the anchor cable dynamometer numerical mutation,the more violent the rock burst energy and the mining earth-shock.Thus,the above research results can be expected to provide a guide for the safety mining of panel 83003,in the way of forecasting and controlling the rock burst in time,which is also valuable for the safety mining of similar coal mines and panels.