Technology Research Of Tongjia Village Tunnel In Subsurface Excavation Method

In recent years, as China’s high-speed rail technology continues to developing, to overcome the aerodynamic problems caused by high-speed train running in the passenger line tunnel, large section tunnel is increasing. Due to the poor ground conditions, for the weak surrounding rock, it requires tunnel face itself put forward higher of stability. And in the construction the stability of the working face or not will have an important impact to the stability of the entire tunnel. Currently, the research tunnel face deformation characteristics, stability discriminant and other aspects of discrimination is still in the exploratory stage. The corresponding systematic research and the applicability are not strong, and there is a certain gap between the actual requirements.(1)According to the monitoring result estimated,it can be achieved surrounding rock parameters of subsurface excavation method of Tongjia Village Tunnel through the BMP2000 parameter inversion and parametric finite element forward.(2)According to the previous detailed introduction of subsurface excavation method,the author firstly optimizes excavation parameters,including height of arch,verifying the stability of the slope, backfilling time, and carries out numerical simulation aiming at key technologies of subsurface excavation method when tunnel is being excavated, such as step length,step height,cyclic footage etc.From the comparing aspects of displacement around the tunnel,plastic zone distribution in surrounding rock,tunnel face extrusion deformation and internal force of the structure,it can be concluded the most suitable method combined with the actual construction situation.(3)According to the whole construction process of subsurface excavation method and conclusion of optimized construction method, the paper determines some key technology parameters during the construction process, such as construction of arch protection,dealing with the border of shadow processing, stability of arch protecting structure and stability of surrounding rock in benching tunnel method.These keytechnologies have significant influence on subsurface excavation method of Tongjia Village Tunnel.(4)According to monitoring results of subsurface excavation method combined with practical engineering construction, the paper evaluates construction effect of subsurface excavation method in Tongjia Village Tunnel.