Study On Carrying Capacity Deteriorating Model And Experimental Research On Shield Tunnel Concrete

China has a large number of cities Crossing the River, across the river, across the sea andgovernance, connected to the river (River), lakes, bay bridge on both sides of the development ofnational economy played a major role. Sea Bridge Crossing the River lakes and rivers, land acquisitionand construction of an underwater tunnel easily demolition, impact on the ground, and does not affectthe water waterway navigable from the harsh effects of climate change, the project is good for hiding,has a strong resistance the advantage of the war-torn ability, has been attached great importance to thecity. Compared to concrete structures in atmospheric environment, the shield tunnel concrete segmentstructure very poor conditions of service, the complex and serious durability issues. In this paper, acombination of theoretical analysis and durability test, study Shield Tunnel concrete segments in thefailure mechanism under the multi-factor coupling model and its durability degradation law, combinedwith higher theory of reinforced concrete, was established to the carrying capacity of guidelines, andconsider a variety of factors coupling durability life prediction model. The model to the measured dataand the model predicted three practical engineering, the results show that the model has a certainpracticality. The full text of the main contents and conclusions are as follows:1、Overview of the current domestic and international concrete elements in the multi-factorscoupling describes the progress made and pointed out the problems; detailed description of the testprograms and modeling methods used in this study.2、Description of the test with the kind of raw materials, origin, physical properties and chemicalcomposition; describes the whole process of the production tube sheet; pointed out that the testmethods used in the durability test and a data processing method.3、Detailed analysis of the durability test results of various data processing, including the analysisof the relative dynamic elastic modulus the carbonation test result analysis, erosion of the results ofanalysis of the chloride ion, sulfate erosion XRD spectra analysis, corrosion segment surfacecracksform, bearing capacity performance test results (including the the fissure condition, crackingload and ultimate load, the load-deflection curve, concrete strain), the steel corrosion. The analysiscompared the test results of of same complexes than tube tablets in different corrosive solution, acomparative analysis of the different mix than the pipe piece of test results in the same kind ofsolution.The results show that: the coexistence of chloride ions and sulfate ions, sulfate can ease thechloride ion erosion of the concrete and the internal reinforcement; continued energized1A current22d, Nanjing subway ratio segment, no case of sulfate corrosion of earlycrack load decreased by 30.4%and39.1%, respectively, ultimate load decreased by32.2%and36.3%, respectively; mixdesign segment, sulfate corrosion case first crack load decreased by35%and40%, respectively, andthe ultimate load decreased37.6%and38.5%, respectively; segment outside the internal rebarcorrosion layer mainly the outer and inner steel corrosion rates were17.7%、2.3%, and the ringserious than the longitudinal reinforcement steel corrosion, the outer ring reinforced with longitudinalreinforcementthe corrosion rates were20%and15.3%, and the inner ring to the reinforced withlongitudinal reinforcement corrosion rate of2.5%and2.1%, respectively; stray current and chlorideions coexist, can not use the method of determination of steel banding segment are attached to steelcorrosion rate.4、Double reinforcement of flexural components bearing capacity formula based on durabilityfactors to consider carbonation, stray current, chloride, sulfate ions, and establish the bearing capacityof the of shield tunnel concrete segment in the multi-factors couplingdegradation model.5、Verification of the bearing capacity and corrosion time the model test data, the results show thatthe calculated results in good agreement with the experimental results.6、Qingdao Jiaozhou Bay undersea tunnel, the Nanjing subway tunnel, Xining rail transit threepractical engineering background model in accordance with the shield tunnel concrete segmentpreliminary life prediction, the results show that: Qingdao Jiaozhou Bay undersea tunnel, Nanjingsubway tunnelThe and Xining the rail transit DURABILTY are to meet the design requirements of100years.7、Summarized the full text of conclusions, further research proposals.