Xue Huajun

Mechanical Properties of New Concrete-Filled Steel Tubular Support

Concrete-filled steel tubular (CFST) support has been gradually applied in the underground projects. According to the loading characteristics of underground projects supporting, the mechanical properties of CFST supports in roadway was analyzed by using theoretical analysis, laboratory tests and numerical simulations. The ultimate bearing capacity (UBC) of φ140×4.5mm CFST short column with the concrete strength of 26.8MPa was 1115.5kN by using the (UBC) formula deduced from the limit equilibrium theory, which was greater than the sum of that of the empty steel stub short column and that of the plain concrete short column. In the mechanical test of CFST support, the ultimate bearing capacity of the supports were 1.35 times larger than those of CFST short column because of the limitation of loading restrictive condition and the influence of the pole instability and eccentric compression on the whole CFST support. In the ABAQUS numerical simulation, the CFST support with the conditions of lateral confining loading constraint and horizontal restraint, the values of yield load and ultimate load of the CFST supports were two times larger than those of the short-column. Meanwhile, the CFST support had a large plastic deformation and its deformation rate could be up to 9%, so it can release the rock mass pressure energy by the deformation of the rock mass. And the support had a higher bearing capacity. So the CFST support was particularly suitable to support the roadway, especially the high ground stress deep roadway and extremely soft rock roadway.