Abstract:

The ground extension of tunnel entrance/exit under the influence of existing surrounding environment is difficult, as a result, a case study of Yingpan Road Tunnel in Changsha is carried out. A composite structure scheme of bridge, tunnel, road and embankment is proposed based on the actual characteristics of bridge and tunnel connection project, and the feasibility of the scheme implementation is analyzed and expounded in detail. The force simulation and calculation results of the composite scheme by Plaxis2D finite element software show that the coordination deformation between the retaining wall and tunnel structure is achieved, and the connected transverse and longitudinal beam structures can effectively connect the retaining wall with the tunnel structure and play a role in the overall stress. Meanwhile, the field monitoring is carried out during the construction, and the monitoring results show that the cumulative maximum settlement and maximum horizontal displacement around the embankment are 15.44 mm and 6.72 mm, respectively, which are smaller than simulation results. The simulation results play a certain guiding role in the construction. By adopting the composite structure scheme, the original landform of the project is protected to the utmost, and the normal traffic under special conditions are guaranteed.

Key words: tunnel engineering, bridge engineering, composite structure of bridge, tunnel, road and embankment, numerical simulation, force analysis, field monitoring