Abstract:

The concretefilled steel tube is characterized by high strength and good plastic toughness. Present, the research on the evaluation index of bearing capacity of concretefilled steel tube arch frame is insufficient; thus, selecting steel tube is difficult. To promote the application of concretefilled steel tube structure in tunnel engineering, based on the comparative analysis of the theoretical calculation and numerical simulation of the bearing capacity of 50 concretefilled steel tubular arches with different diameters and wall thicknesses, the evaluation indices and reasonable selection of the concretefilled steel tubular arches for highway tunnels are studied. The results show the following: (1) Compared with the area, steel content and moment of inertia of steel tubes, the flexural section coefficient of steel tubes as a comprehensive index can find the relationship between the bearing capacity of steel tubes and concretefilled steel tubes, and it is used as an index to evaluate the bearing capacity of concretefilled steel tubes. (2) Based on the research results, the formula of flexural section coefficient of the steel tube and the bearing capacity of concretefilled steel tube arch and that of the bearing capacity of the primary support and the concretefilled steel tube arch are fitted. (3) The diameter of the steel tube has a greater effect on the bearing capacity of concretefilled steel tube arches than the thickness of the steel tube. The largediameter and thinwall concretefilled steel tube arches have a higher bearing capacity, and it is economical. (4) It is suggested that the concretefilled steel tube arch is selected based on the following priority order: large diameter, large thickness, and improved core concrete strength.

Key words: highway tunnel, concretefilled steel tube arch, bearing capacity evaluation index, steel pipe bending section coefficient, steel pipe selection