基于微震监测的岩爆预报在引水隧洞施工中的运用

Application of microseismic monitoring based rock burst prediction to construction of diversion tunnel

为实现锦屏Ⅱ级水电站引水隧洞和排水隧洞在施工期间可能发生的强烈岩爆的预报,本文制定了基于微震监测技术的岩爆预报方案。首先对微震监测系统收集到的微震信息进行滤波处理和波普分析。然后,根据微震信息进行微震源定位,同时得到微震事件的数量、释放能量、视体积、能量指数等指标。最后,根据这些指标的值及其变化规律并结合现场地质条件预测隧洞发生岩爆的概率和强度。现场岩爆情况与采用该方法的岩爆预报结果对比表明:该预报方法对高强度岩爆具有较高的准确率。

In order to realize the prediction of the strong rock bursts those possibly occur during the construction of both the diversion tunnel and the discharge tunnel of Jinping Ⅱ Hydropower Station, a rock burst prediction scheme is made herein based on the microseismic monitoring technology. First of all, the microseismic information gathered by the microseismic monitoring system is filtered with analysis made on its spectrum. Afterwards, not only the microseismic source is positioned according to the relevant microseismic information, but the indexes such as the amount, the released energies, the apparent volume, the energy indexes, etc. of the microseismic events are also obtained simultaneously. Finally, in accordance with these indexes and their changing laws, the probability and intensity of rock burst that possibly occur inside of the tunnels are predicted under the consideration of the in situ geological condition. The comparison between both the rock burst occurred on site therein and the predicting result from this method is demonstrated that this method has a high accuracy for predicting the rock burst with high intensity.