Study On Mechanical Properties Of U-type Confined Concrete Arch Centering And Its Application In Deep Roadway

Supporting of deep soft rock roadway is always one of the important problems in the field of mining. Aiming at deep soft rock roadway and roadway with structural fracture zone, new support form—U-type confined concrete arch centering was developed, and axial compressive performance of its basic building block (short column) was researched by lab experiment, numerical simulation, on the basis, the mechanical properties of the arch centering, which were carrying capacity, force characteristic, deformation behavior and law and so on, were researched by numerical simulation and field test, and so was the surrounding rock controlling effect of the arch centering. The main work in the thesis includes:1. Lab experiment study on mechanical properties of short column. Axial compression experiment of U-shaped steel short columns and U-type confined concrete (UCC) short columns were carried out, by which the instability and failure mode, carrying capacity and law for deformation and failure of the two short columns were researched. And the fracture mechanism of core concrete was researched by acoustic-emission techniques.2. Numerical simulation study on mechanical properties of short column. Nonlinear finite element models of UCC short columns under axial load were bulit, of which the correctness was verified by contrastive analysis. On this basis, ultimate bearing capacity computing formula of UCC29short column was obtained by the regression of computed result, which considered the variation of seal plate thickness and concrete strength. With economical efficiency evaluating indicator and stress concentration factor built, quantitative evaluating indicator for UCC arch centering selection was put forward.3. Three dimensional finite element modelling study on the arch centering. Load test numerical model of U-type confined concrete arch centering was bulit, carrying capacity, and the force characteristic, deformation behavior and law of three kinds of UCC arch centering under uniform load were analyzed. Based on the typical geology condition of Zhaolou coal mine, the deformation characteristics and the instability and failure mode of UCC arch centering with surrounding rock pressure were researched by numerical simulation. Based on computed result, selective preference of UCC arch centering was conducted by comprehensive analysis of load-carrying properties and economical efficiency of three kinds of UCC arch centerings.4. Field test study on the arch centering. Considering the characteristic of Second dip entry in Zhaolou coal mine, UCC arch centering support plan was designed, and the field test was carried out, and the surrounding rock control effect of UCC arch centering was analyzed by field monitoring.