Ultra-High Performance Concrete For Road Tunnels Research On Prefabricated Reinforcement Methods

The present arch reinforcing approach has focused on how to make sure that the highway tunnel lining reinforcement structure is thin enough to meet the engineering criteria while also making sure it does not invade,according to China’s research on the subject.In this study,a brand-new reinforcement technique is put forth,involving semipost-pouring assembly and composite constructions made of ultra-high performance concrete(UHPC)and regular concrete(NC).It was decided how to calculate the cracking bending moment and the positive section bearing capacity of the composite beam after performing bending tests and numerical simulations on the UHPC-NC composite beam’s component parts.The following are the primary findings and research recommendations:(1)To determine the compressive performance of UHPC and C50 concrete,the material properties of the two types of concrete were tested.To investigate the flexural bearing performance of UHPC-NC composite beam components,ten UHPC-NC composite beam specimens and two pure concrete beam specimens were built.(2)Pure bending rib failure occurred in UHPC-NC composite beams treated with keyways,while oblique shear failure happened in composite beams not treated with keyways.The bearing capacity of the composite beam increases with specimen crosssectional thickness along with bending stiffness;however,the cross-sectional thickness of the specimen with a section thickness of 120 mm increases with thickness of UHPC,whereas the specimen with a cross-sectional thickness of 150 mm does not significantly increase.(3)The cracking bending moment and positive section bearing capacity of the UHPC-NC composite beam are estimated using a formula,and the test results and calculated results are compared.The difference between the two is very small,proving the applicability of the formula.(4)Abaqus finite element software was used to verify the UHPC-NC composite beam test,and the findings demonstrated good agreement between the test and simulation.The results demonstrate that the axial force can effectively improve the bending bearing capacity of the composite beam within a particular range as the working condition of the beam’s bending bearing capacity is raised.(5)The bearing characteristics of the lining of the two-lane diseased highway tunnel reinforced by UHPC-NC composite structure were studied using a three-dimensional finite element model.The results showed that the ultimate bearing capacity of pure NC reinforced structure with a cross-section thickness of 250 mm and 200 mm was higher than that of UHPC-NC composite reinforcement structure In actual engineering applications.