Flexural performance test and finite element analysis of UHPC-NC composite beam

There are no sufficient researches into the umbrella arch method for highway tunnel reinforcement. Finding a way to ensure the lining has enough bearing capacity to meet the engineering requirements under the premise that the highway tunnel lining reinforcing structure is not thinned beyond its limit is now a high priority in the research into umbrella arch method. This paper proposes a new reinforcing method, where a composite structure built of ultra-high-performance concrete (UHPC) and normal concrete (NC) is used to reinforce the lining. The flexural test and numerical simulation of UHPC-NC composite beam member have been conducted, so as to investigate the flexural bearing capacity of the reinforcing structure from the aspect of members. According to the results, greater thickness of section results in greater bearing capacity of composite beam and greater flexural stiffness. Increasing the UHPC thickness will increase the bearing capacity of the specimens with 120 mm thickness of section, but will not significantly improve the bearing capacity of the specimen with 150 mm thickness of section. Greater roughness of composite material interface results in greater bearing capacity and better crack resistance of the specimens.