Rockburst risk analysis based on microseismic monitoring in deep-buried tunnel with TBM excavation

Tunnel boring machine (TBM) should face high rockburst risk directly in deep-buried tunnel in hard rock. Real-time microseismic monitoring on rockburst risk analysis is carried out during TBM construction in the #3 diversion tunnel of Jinping II Hydropower Station. The correlation between rockburst and microseismic activity is researched. The results show that: (1) The spatial distribution of rockburst and microseismic activity has a good correlation with each other that both are characterized with regional concentration and all moderate and strong rockburst occurred in areas of concentrated microseismic activity. (2) It is better to analyze rockburst risk based on multiple seismic parameters. (3) Comprehensive parameter seismic Schmidt number can be well used for rockburst risk analysis in deep-buried tunnel with TBM excavation. Therefore, microseismic activity spatial distribution, multiple seismic parameters and seismic Schmidt number can be used together for rockburst risk analysis in deep-buried tunnel with TBM excavation.