ABSTRACT
Through numerical simulation, the vertical displacement and horizontal displacement of surrounding rock during excavation of multi-arch tunnel are revealed. The stress mechanism of surrounding rock, lining structure and middle partition wall of multi arch tunnel is analyzed. Based on the project example of Bailongpo tunnel of Wuyi expressway in Yunnan, the construction technology without middle drift and monitoring method of multi-arch tunnel are described. The results show that: (1) The construction technology without middle drift is feasible. (2) The deformation characteristics of tunnel have obvious space-time effect, and the better the quality of surrounding rock, the smaller the deformation value and the shorter the stability time. (3) The bias effect of the following tunnel is very obvious. (4) The middle wall must have enough strength and stiffness to ensure the stability. It is the key and foundation for the construction of a double-arch tunnel.
