Abstract:

Yumiao tunnel is a twintube 4lane highway tunnel under shallow cover. Due to the soft surrounding rock, the ground water and the varying geological conditions, collapse occurred in the exit section of the left tube in the early stage. In the paper, analysis is made on the causes for the collapse of Yumiao tunnel, solution consisting of grouting reinforcement executed from the ground surface and from inside the tunnel and improving the support structure parameters is proposed, and analysis is made on the solution of grouting from inside the tunnel by means of numerical simulation. In the end, appropriate solutions are made. The practice demonstrates that the solutions adopted for the collapse are safe, feasible and cost efficient and can guarantee the quality of the tunnel.

Key words: Yumiao tunnel, collapse, numerical simulation, highway tunnel, soft surrounding rock, grouting reinforement