Study on Bonding and Slipping Mechanical Properties of Steel Reinforced Concrete in Tunnel
The bonding and slipping properties of profile concrete in the initial tunnel support have an important influence on the synergistic deformation of the support and the overall bearing capacity.In this paper,two sets of roll-out tests were conducted to analyze the damage characteristics of the specimens,and numerical simulations were carried out with finite element software to obtain bond-slip curves and analyze the bond-slip performance of the specimens for whether steel fibers were added to the combined steel and concrete structure.On this basis,the influence law of steel fiber doping on the characteristic load of the specimen was analyzed,and the characteristic bond strength was obtained by calculation.The test results show that:(1)the damage mode of the specimen is longitudinal splitting damage;(2)the concrete crack morphology of the specimen mainly includes:extending to the four corners in the direction of 45° and perpendicular to the middle of the flange;(3)the bond-slip curve of the specimen can be roughly divided into four stages:no-slip segment,slip segment,falling segment and residual segment;(4)the incorporation of steel fibers does not significantly improve the ultimate load and ultimate strength values of the profile concrete push-out structure,but it can improve the residual load and residual strength values of the profile concrete push-out structure;(5)the results of numerical simulation are ideal and the error is small.The conclusions obtained can provide reference for the study of the failure characteristics of the initial support structure of the tunnel,and the formulation of tunnel design and construction engineering measures.
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