Abstract:

For the reconstruction and expansion of multiarch tunnel of a 4lane highway in Anhui Province, ten kinds of reconstruction and expansion schemes are proposed. The ten schemes are qualitatively analyzed in terms of driving safety, how to take full advantage of existing tunnel and organize traffic easily, etc. According to the result, three better schemes are selected, and then quantitatively compared and analyzed from the aspects of engineering cost, construction difficulty and pressureoccupying mineral resources, and numerical simulation method is used to analyze the two schemes of tunnel insitu expansion. The simulation results show that: (1) Strong support in reconstruction and expansion of largesection tunnels can effectively control tunnel deformation. (2) The displacement and stress of the tunnel can be controlled in the construction with scheme 1 and scheme 2, and the maximum axial force values of the two schemes are similar, but the displacement control effect of scheme 2 is better. (3) For the reconstruction or expansion of largespan tunnels, attention should be paid to tunnel arch settlement and arch bottom bulging, and the problem of arch bottom bulging is more prominent.

Key words: multiplearch tunnel, reconstruction and expansion scheme, numerical simulation