Study on the Control of Large Deformation of Initial Support and the Timing of Secondary Lining in Phyllite Tunnel
Phyllite tunnel has obvious characteristics of large deformation,long deformation time,and difficult support,which has been one of the important problems in transport construction.This paper took Miyaro No.3 Tunnel as the engineering background,analyzed the deformation and damage mechanism of the tunnel through on-site investigation,and determined the joint support method of long and short grouting anchors for large deformation of the tunnel initial support,and the 42nd day after tunnel excavation as the choice of the secondary lining of the tunnel.Field practice shows that,after adopting the determined control programme for large deformation of surrounding rock,the tunnel vault settlement and horizontal convergence are stable at 159.6 mm and 127.4 mm respectively,and the surrounding rock stress generated by the secondary lining is very small and uniformly distributed,which indicates that,after adopting the initial support large deformation control technology,the tunnel initial support has a strong supporting capacity,which can effectively reduce the secondary lining pressure of the tunnel and play a vital role in the long-term use of the secondary lining.The results of the study can provide technical guidance for the control of large deformation and construction of tunnels in phyllite.
phyllite tunneltiming of applicationlong and short grouting anchorssecondary lininglarge deformation control
NETL
NSTL
万方数据
