Abstract:

The rockburst is one of the major disasters in deep tunnel construction. Hence, the safety and efficiency of open TBM boring in strong rockburst formation should be ensured. A targeted technical system of strong rockburst prevention and control is formed based on years of practice and research on the prevention and control measures for rockburst in Lingnan TBM section of Qinling Tunnel of Hanjiang RiverWeihe River Water Conveyance Project. The study results show that: (1) The possible rockburst level within 15 m ahead of tunneling face can be roughly deduced by using microseismic monitoring rockburst advanced prediction system and continuous analysis and correction of the monitoring data. (2) The scale and frequency of rockburst after TBM passing through can be reduced by adopting rational predrilling stress release pretreatments. (3) The rapid sealing of the surrounding rock in the high rockburst risk zone can be realized by optimizing the treatment process. (4) The damage of primary support induced by hysteresis rockburst can be prevented by using proper supporting materials. The prevention system contributes to the construction safety control of the strong rockburst formation, and can also reduce the construction schedule. The results can provide reference for similar projects in the future.

Key words: tunnel, open TBM, strong rockburst, control measures, rockburst prediction, advanced pretreatment