关键词: 双向开挖隧道;隧洞贯通段稳定性;隧洞破坏模式;超前支护;

Abstract: Stability of breakthrough section has a great influence on safety of double heading construction tunnel. In order to evaluate the stability of the breakthrough section of soil tunnel, a potential failure mode and a calculation method of safety factor are proposed based on analytical method, and the numerical simulation method is furtherly used to verify the failure mode of the tunnel breakthrough section and the safety factor. On this basis, we study the improvement effect of the advance support on the stability of the breakthrough section. Aiming at a soil tunnel in a pumped power station, the stability and reinforcement of the breakthrough section are analyzed. The results show that the breakthrough section of the soft soil tunnel shows a double-slip failure mode under the similar disturbance at both sides. Advanced support can significantly improve the stability of the breakthrough section. Using pipe roof in extreme disturbance conditions, the factor of safety (FoS) increases from 1.06 to 1.15. Jointly using the pipe roof and glass fiber anchor as support, the FoS increases to 1.23. This method provides a certain basis for studying the stability of breakthrough section of soil tunnels.

Key words: double heading construction tunnel; stability of tunnel breakthrough section; failure mode of tunnel; advance support