Abstract:

Yuntunbao tunnel on ChengduLanzhou railway is more than 20 km long. The construction of the approach works to the entrance and exit of Yuntunbao tunnel has already been started before the construction of Yuntunbao tunnel. In the paper, two options, i.e., the option of single doubletrack tunnel tube and the option of double singletrack tunnel tubes, are proposed for the tunnel, and comparison and contrast is made on these two options in terms of disaster prevention and rescue, project investment, construction risk control, construction organization, adaptability of the support structure to the serious deformation of the soft rocks, seismic resistance of the tunnel structure, mucking, environment protection and operation ventilation. It is concluded that the option of single doubletrack tunnel tube can be adopted for Yuntunbao tunnel. 

Key words: ChengduLanzhou railway, superlong Yuntunbao tunnel, single doubletrack tunnel tube, twin singletrack tunnel tubes, option analysis