Research on Influence Factors of Bearing Capacity of Concrete-Filled Steel Tubular Arch for Traffic Tunnel

Abstract

When a traffic tunnel passes through special strata such as soft rock with high geo-stress, expansive rock, and fault fracture zones, the traditional supporting structure is often destroyed due to complicated loads, which threatens the construction and operation safety of tunnel engineering. Concrete-filled steel tubular (CFST) structure gives full play to the respective advantages of steel and concrete and has better bearing capacity and economic benefits than traditional support structure, which has achieved good results in some underground engineering applications. In order to promote the application of CFST in the construction of traffic tunnels with complex geological conditions and improve the bearing capacity of the initial supporting structure of tunnels, the influencing factors of the bearing capacity of CFST arch were studied by numerical simulation. The main achievements are as follows: (1) The load-displacement curves of CFST members under different material parameters are basically consistent. CFST members have significant restrictions on displacement in the elastic stage and have high ultimate bearing capacity. Although the bearing capacity decreases obviously after reaching the peak, it shows good extension performance. (2) The height of the steel tube section, the thickness of the steel tube wall and the grade of the core concrete have an approximately linear positive correlation with the bearing capacity of CFST arch, but the influence of these three factors on the bearing capacity of CFST arch decreases in turn, and when the grade of core concrete increases above C50, it has no significant effect on the bearing capacity of members.

Calculation model of concrete-filled steel tube arch bridges based on the “arch effect”

“…The steel tube at the arch foot will uplift obviously and the hoop action of the steel pipe on the concrete will fail when the CFST arches reach the ultimate bearing capacity. Li and Lei (2022) studied the influencing factors of the bearing capacity of CFST arches by numerical simulation and found that the arch had a great limitation on displacement in the elastic stage, and the ultimate bearing capacity was relatively high. The bearing capacity decreases obviously after reaching the peak value, but it showed good elongation performance.…”

Numerical investigation of ultimate bearing capacity of circular and square concrete-filled double steel tubular T-joints

“…The benefits of these concrete-filled steel tube (CFST) structures have been investigated by numerous researchers in the technical literature. [7][8][9][10] Packer 11 tested rectangular CFST connections, where substantial strength enhancement was seen when the infill concrete was involved. Liu et al 12 experimented with the impact of infill concrete in circular hollow section (CHS) and rectangular hollow section (RHS) steel tube elements.…”