Optimization Analysis of Double-side Wall Construction Method for Super-large Section Shallow-buried Bias Tunnel
Because of the large span-depth ratio of four-lane super-large highway tunnel,how to ensure the construction safety,and optimize the construction process and find the deformation law of tunnel surrounding rock under shallow-buried bias is of high research value.Taking the one-way four-lane Qianou Tunnel as the research background,the deformation laws of different construction procedures are analyzed through field tracking monitoring and finite element calculation methods.The analysis results show that the process of first excavating the left and right side pilot tunnels and then excavating the core soil produces less surface settlement than the process of first excavating the upper half and then excavating the lower half;The different processes show that the surface settlement on the deep side is greater than the surface settlement of the shallow side(the buried depth is asymmetrical settlement trough);The process of first excavating the deep side of the buried depth produces less surface settlement than the process of first excavating the shallow side of the buried depth;The surface displacement and the displacement around the cave caused by the removal of 20m vertical temporary supports at a time are both larger,the length of the vertical temporary support removal should be reduced;When the working face is 2D from the observation section(D is the span of the tunnel after the initial support is formed),the excavation has less influence on the deformation,and it is a suitable time for the second lining.
tunnelsshallow-buried bias tunnelstwo-side wall construction methodprocessesdeformationoptimization
NETL
NSTL
万方数据
维普
