Study on mechanical properties of fabricated concrete-filled steel tubular temporary inverted arch structure

In order to improve the cyclic utilization rate and disassembly convenience of temporary support in tunnels under bad geological conditions, and improve its anti-deformation strength and comprehensive construction performance, a new type of segmented fabricated concrete-filled steel tube temporary inverted arch structure was proposed.The steel tube was filled with concrete as the main structure body, supplemented by unloading quick dismantling connection components.By setting the load conditions under four buried depths, the mechanical properties of each segment and the overall disassembly performance of the inverted arch structure under different working conditions were studied by numerical simulation and physical test verification.The results showed that the force of the temporary inverted arch structure proposed in this paper had a symmetrical force distribution, the maximum values appeared at both ends of the inverted arch, and the zero points of bending moment and shear force were approximately at the one third points of the whole structure, so as to determine the installation position of the unloading quick dismantling connection components.The stress distribution position under different buried depth loads was fixed and would not change with the increasing of load, so as to ensure the safety and reliability of the whole structure, and can cope with various working conditions, and the disassembly force was only 210.6 N under the condition of 90 kN axial compression, the manual use of the wrench can easily and quickly complete the structure disassembly.