Abstract: In order to clarify the basic mechanical properties of the latest invented U-type confined concrete arch centering, the axial compression experiment program of U-type confined concrete (UCC) short columns is designed. And from the aspect of deformation and failure modes, load-strain curves, ultimate bearing capacity, core concrete response characteristics of the acoustic emission and so on, the mechanical behavior, deformation and failure character are analyzed, and the fracture mechanism of core concrete is researched. The study result shows that the failure modes of UCC short columns under the axial compression is in overall plastic instability, and the N-ε curve shows the rise → gently rise 4 stage type. UCC short columns have better ductility and post-bearing capacity, with the ultimate beating capacity increasing by 127%~196%. Accordingly, the economy improves. Acoustic emission activity shows 4 periods: incubation → active → stabilization → elimination death. At the same time the deformation & failure behavior and mechanism of UCC short column are obtained by comprehensive analysis. The application effect shows that UCC arch centering is a new effective support for deep and soft rock roadway, and the surrounding rock controlling effect is much better than U-steel arch centering.

Key words: U-type confined concrete, arch centering, short columns, axial load, mechanical properties, bearing capacity, acoustic emission