Abstract:

Comparison between bench method and fullface method (including invert arch) for soft rock section of Ping’an Tunnel on ChengduLanzhou Railway is made in terms of surrounding rock deformation, primary support stress and construction organization by using numerical simulation, theoretical calculation and site test. The study results show that: 1) The stability of surrounding rock of tunnel constructed by bench method is superior to that constructed by fullface method; and the accumulated deformation of tunnel constructed by fullface method is smaller than that constructed by bench method. 2) The sizes of shear zone and tensile failure zone of tunnel constructed by 2 methods are almost the same. The construction quality of tunnel constructed by fullface method is easier to control. 3) The fullface method is superior to bench method in terms of labor and construction schedule.

Key words: soft rock tunnel, phyllite, bench method, fullface method (including invert arch), construction organization