Analysis of Secondary Lining Support Time and Load Distribution in Bi-arch Tunnel

The data from monitoring the convergence of the surrounding rock and the arch were analyzed based on the on-the-spot monitoring of a bi-arch tunnel.According to the variation law of the convergence lines,the relationship between the stress in tunnel and the best time of secondary lining was analyzed.The results show that the surrounding rock of the tunnel becomes stable after 46 days and the final stress of the secondary lining is small.