微震监测技术在深井矿山中的应用

APPLICATION OF MICROSEISMIC MONITORING TO DEEP MINES

冬瓜山铜矿是目前国内地下开采最深的金属矿山之一,岩石具有典型的岩爆倾向性。为了掌握岩爆发生规律,评估其危险性,保证生产安全,2005年8月矿山安装了南非ISS公司的微震监测系统。通过对现场定点爆破的测试,校验了系统的定位参数,实现了对采矿活动过程中围岩应力状态的实时监测。简单介绍了冬瓜山微震监测系统的组成及网络布置,基于对2 a多微震事件数据的处理,研究了波形的分析方法,对比了手动处理与系统自动处理的定位精度;依据波形与生产活动的对应关系,对检测到事件的波形进行了分类研究,确保了事件的及时识别和分类保存。基于量化的地震参数,特别是利用等值线、回归曲线和时间变化曲线与采矿活动的对应关系,重点分析研究了2006年8～10月3个月内发生在54#勘探线隔离矿柱的微震事件参数,对隔离矿柱内出矿巷道破坏机制进行了研究。研究结果表明,发生破坏前岩体刚度先逐步增大然后又下降,应力水平先下降后又转而增大,微震事件活动率增加,累积视在体积急剧增大等,这为井下矿山巷道和矿柱破坏机制以及破坏的预报预测研究提供了一种新方法。

Dongguashan Copper Mine is one of the deepest metal mines in China presently, where the rocks are typically burst-prone, in order to better understand the regularities of rockburst occurrence, an ISS microseismic monitoring system manufactured in South Africa was installed in Dongguashan Copper Mine in August, 2005. The positioning accuracy of the system has been adjusted according to the blasting test, by which the real-time monitoring stress state of rock mass corresponding to mining is realized. The composition and layout of the monitoring system in Dongguashan Copper Mine are briefly described. Based on analyzing the seismic events in the last two years, the process of different shapes of microseismic event waveforms has been studied. Comparative location results from automatic processing and artificial processing have also been made. In terms of the corresponding relations between recorded waveforms and practical mining, the event waveforms were assorted, which will ensure events timely being identified and stored according to their characteristics. Based on quantized microseismic parameters, especially using the corresponding relations between contour line, regression curve, time history and mining practices, the microseismic events occurring during the three months from August 2006 are primarily analyzed; and the failure mechanism of the rib pillar at exploration line 54 is also studied. The results indicate that rock mass stiffness gradually increases first and then declines; rock mass stresses decline from normal level and then raise sharply; the seismic activity and cumulative apparent volume increase rapidly before the large scale failures of rock mass. This provides a new approach for the study of failure mechanism of mining structure and the damage prediction.