The Study On The Bond And Bending Capacity Of Near-surface Mounted FRP Rods In Tunnel Secondary Lining

With the constant progress and development of tunnel engineering in our country,China is the largest number of tunnel and underground engineering in the world,with the fastest developing speed,the most complicated geological and structural form of country,we have to face a big problem that a large number of tunnel has entered the stage of "maintenance",after a long-term operation,part of the tunnel in the hole behind the lining crack,water leakage,lining and so on obvious diseases,endangering the safety of traffic.And secondary lining as the main structure of the tunnel,is very important for the technology condition of tunnel operation safety,so the tunnel secondary lining reinforcement technique has become a core content of tunnel reinforcement.FRP-fibre reinforced composite material,is made up of fiber and matrix materials mixed in certain proportion after the formation of the type of high performance material,because of its superior mechanical properties are widely used in bridge engineering,various types of’ civil construction,Marine engineering,and underground engineering.Fiber composite materials referred to as "FRP" due to its advantages of light weight,high strength,good corrosion resistance,the FRP material is finding wider and wider application in the field of’ civil engineering reinforcement.FRP reinforcement technology is convenient and quick,do not increase the weight of structure and corrosion resistance and other characteristics compared with the traditional strengthening methods have prominent advantages,especially the embedded reinforcement technology,fully improve the efficiency of the utilization of FRP and reinforcement.In this paper the embedded FRP tunnel second lining reinforcement technology research mainly focus on flexural bearing capacity of the reinforced,bond slip behavior between FRP and concrete research and theoretical analysis of crack the main research contents and results were as follows:(1)based on the stress and strain softening model,by using the method of numerical simulation research of FRP composite material in the second lining of the bonding effect,describe the failure process and type,analysis of material parameters and the parameters of the contact area on the final failure pattern,the effects of bond strength and the principle analysis,analysis interface related characteristics at the same time,to provide basis for selecting reasonable reinforcement material parameters.(2)the research of FRP embedded reinforcement of secondary lining concrete flexural bearing capacity,the influence of the tunnel secondary lining structure in the centripetal force analysis under uniformly distributed load,analyzes the characteristics of deformation and failure process,comparing with FRP embedded reinforcement after the change of the flexural bearing capacity of structure as a whole.(3)the research of FRP composites reinforcement scope of reinforcement,reinforcement method and slot size effect on the final reinforcement effect,including failure modes,deformation characteristics and the change of bearing capacity.