深埋隧洞TBM掘進微震實時監測與特征分析

馮夏庭　陳炳瑞

摘要：針對深埋硬巖隧洞TBM 掘進過程中開展微震實時監測存在的困難與不足，對現有微震監測技術進行優化與改進，并在錦屏II 級水電站3#引水隧洞TBM 施工洞段開展微震實時監測。監測結果表明：（1） TBM 施工環境噪音復雜，但主要噪音特征明顯，可通過建議的濾波方法有效濾除。（2） 圍巖的微震活動和TBM 掘進及掘進速率具有明顯的關系，TBM 掘進速率增加，圍巖微震明顯活躍；TBM 掘進速率降低，圍巖的微震活動明顯降低；微震平靜期發生在TBM 檢修期間，最活躍期發生在TBM 檢修后掘進4～6 h。（3） 一些巖爆發生前，微震事件和能量釋放在空間上由隨機離散狀態變得相對集中，在時間上微震事件的數量和能量有一個迅速增加的趨勢；視體積有突增趨勢，能量指數有突然下降跡象。（4） 在深埋隧洞TBM 掘進過程中進行微震實時監測，可以獲得巖爆發生前的有效微震信息，獲得巖爆發生前微震活動的演化特征與規律，為巖爆的發生提供較為準確的預警信息。因此，通過微震監測預測預報深埋隧洞TBM 掘進過程中巖爆的發生是可行的。

關鍵詞：巖石力學；微震監測；巖爆預測；深埋隧洞；TBM；能量指數；錦屏II 級水電站

Abstract：According to the difficulties and shortcomings of real-time microseismic monitoring during tunnel boring machine（TBM） tunneling with overburden of over 2 000 m-thick hard and brittle rock mass，the traditional microseismic monitoring technology，used in the mines，is optimized and improved；and the new microseismic monitoring technology is utilized during the TBM tunneling in the diversion tunnel #3 of Jinping II hydropower station. The monitoring results show as follows：（1） The ambient noise is much and complex，but the main characteristic is clear during TBM tunneling；and it can be filtered through the proposed filtering method effectively. （2） There is an obvious relationship that microseismic activity increases with the increase in TBM tunneling rate between microseismic activity of surrounding rock mass and the TBM tunneling rate，vice versa. Microseismic activity is very weak during the period of TBM maintenance，but it becomes most active when TBM working lasts for 4–6 hours after TBM maintenance. （3） Before some rockburst occurred，distribution of microseismic events and energy release gradually convert from discrete to relatively concentrative in spatial domain，the number of microseismic events and the radiated energy increase rapidly in temporal domain；and apparent volume of surrounding rock mass has a sudden increasing trend；energy index has a sudden drop trend in the same time. （4） When microseismic monitoring is carried out during TBM tunneling covered with thickly hard and brittle rock mass，effective microseismic information can be acquired；the evolution characteristic and law of microseismic activity can be found and known；and more accurate early-warning information of rockburst can be provided. Therefore，it is possible and feasible to forecast the occurrence of rockburst by microseismic monitoring.

Keywords：Rock mechanics；microseismic monitoring；rockburst prediction；deep-buried tunnel；tunnel boring；machine（TBM）；energy index；Jinping II hydropower station