Research On Flexural Performance Of Concrete-filled Steel Tubular Support And Its Application

This paper studied the flexural performance of Concrete-filled steel tubular(CFST) straight beams and bending-reinforced ones under the condition of purebending by the ways of theoretical analysis, laboratory tests and numerical simulation.It researched the plane section assumption, deviation law of neutral layer, and theflexural bearing capacity of Φ194×10mm CFST members with the mechanicalcondition of pure bending, and built up the relationship between the displacement andthe deviation value of neutral layer. Based on the test results mentioned above, acalculation formula was built. Some factor effects of the flexural performance wereanalyzed. Moreover, the bearing capacity of the arch-shaped CFST members wasobtained by the laboratory test, and some factor effects were also analyzed. Accordingto the analysis of failure mode of CFST support in extremely soft rock surroundingsupporting project, the reasons for the deformation failure of the support was obtained.Considering the big deformation in the extremely soft rock surrounding, a newsupporting scheme was proposed, which consists of pre-grouting technology,bending-reinforced CFST supports and early-hardening-bending-pressure-relieftechnology, which can realize the stability of the extremely soft rock surrounding.