深埋隧洞岩爆微震监测预警技术

在锦屏二级水电站引水隧洞施工现场构建了隧洞可移动式微震监测系统,实现对掌子面围岩微破裂的连续监测。分析了隧洞常见震动信号的波形特征和隧洞微震监测系统定位误差及其有效性,为高效识别岩石微破裂信号和提高岩爆预警准确率提供保障。研究了锦屏二级水电站施工排水洞极强岩爆过程中的微震事件时空分布和集聚特征,岩爆发生前有明显的微震前兆,微震集聚区的事件密度持续增大和短期内事件数的快速增长可作为岩爆发生的前兆信息。

Early Warning for the Rockburst in Deep-buried Tunnels Using Microseismic Monitoring Technique

A mobile microseismic monitoring system was installed at the Jinping II hydropower station. The system can capture the microcracks of the surrounding rock mass around the working face. To recognize the microcrack signals of rock mass efficiently and improve the reliability of the early-warning for rockburst,the waveform of different seismic signals and the location error of microseismic events are analyzed in this study. The temporal-spatial distribution and clustering characteristics of the microseismic events during an extremely strong rockburst in the drainage tunnel at the Jinping Ⅱ hydropower station was studied,and there are obvious precursors for the extremely rockburst,namely,the event density keeps increasing at the microseismicity clustering zone and a rapid increase in the event count during a short time period.