Abstract: Experiments on the concrete-filled steel tubular (CFST) support under symmetrical and unsymmetrical in-plane loadings have been carried out. Based on the experimental results, this paper studies the deformation, strain, the increasing resistance law of contractible joint and ultimate bearing capacity of CFST arch support. The results show that the CFST support has good elastoplasticity and carrying capacity due to the cooperative work of steel and concrete. Initial imperfection or partial weakening of the support is a major reason for the destruction of the support. The increasing resistance curve of contractible joint can be divided into three stages. The contractible joints should be tightened in a timely manner in accordance with the field monitoring for the bearing capacity fluctuated after slip. Finally, the characteristics of bearing and deformation of CFST arch support are analyzed with ABAQUS software, and the simulated results are fairly close to the experimental results.

Key words: soft rock roadway, concrete filled steel tube, support, contractible joint, ultimate strength