ABSTRACT
The quantitative design and safety analysis of support structure parameters for multi hole space tunnels with small clear distance are a major problem in current design. This paper is aimed at the design of He’ao tunnel in Shenzhen Ji-he Expressway, China. The total safety factor method is used to study and compare the excavation and support modes, excavation sequence and support parameters of the four tunnels. The conclusions are as follows: (1) Based on the principle of total safety factor method, the design method of multi hole space tunnel with small clear distance is proposed; (2) For the spatially small-spaced four-tube tunnels, the excavation and support mode of “excavation of the next tunnel after the secondary lining completion of the first tunnel” shall be adopted, and the excavation sequence shall be tunnel 1 → tunnel 2 → tunnel 3 → tunnel 4. (3) This paper can provide theoretical guidance and reference for similar engineering design.
