Deterioration Analysis Of Prestressed Aqueduct Structure Under Effect Of Multi-damage

With the construction of the South-to-North Water Diversion Project,a large amount of intersecting building adopted the aqueduct.Because the water diversion lines of large aqueducts are relatively long and the natural and geographical environment of them are often complex and diverse,they have suffered from long-term damage,such as freeze-thaw damage,corrosion damage,carbonized damage,and damage caused by uneven settlement of foundations.Under the action of damage,the concrete members of the aqueduct will accelerate aging,the steel bars will accelerate rust,and the aqueduct structure will be damaged and unstable.At present,there is no scholar in the industry to scientifically study the damage deterioration law,working behavior and failure process of aqueduct under the action of multiple types of damage.This paper takes a large three-slot and three-way prestressed aqueduct in the middle route of the South-to-North Water Transfer Project as the research background,and takes the 41 st span of the 30 m span multi-span wall as the research object,and establishes a three-dimensional finite element model in accordance with the engineering practice..Under the three major damage conditions of freeze-thaw damage,pre-stress loss and uneven foundation settlement,the aqueduct is analyzed to research on the damage law,working behavior and damage of the aqueduct structure.The process is as follows:(1)By referring to various experimental data of industry scholars,the deterioration law of constitutive curve of the concrete model of Zhenhai under freezing and thawing is summarized.The freeze-thaw damage of the frozen-melt zone of the aqueduct structure was simulated by the deterioration law of the constitutive curve of concrete.The stress and deformation of the aqueduct’s whole structure and the frozen-thaw zone of the channel were analyzed under different degrees of freeze-thaw damage.The degree of freeze-thaw damage is determined by the influence of the overall structural strength and stability of the aqueduct.(2)Simulate the prestress generated by the steel strand by the cooling method,and simulate the loss of the prestress by the temperature drop.The prestress of the longitudinal,vertical and transverse steel strands of the three types of reinforcements were reduced,and 10 kinds of damage conditions were combined to analyze the stress of the aqueduct structure under 10 prestressed damage conditions.Deformation.Among them,the focus is on the variation of the groove bottom plate and the variation of the stress across the middle section under various prestress loss conditions.(3)Based on the diffusion crack model,the Willam-Warke five-parameter model failure criterion and the concrete damage elastoplastic model,the nonlinear analysis of the failure process of the aqueduct under the uneven settlement of the foundation is carried out.The fracture location,diffusion trend of the aqueduct structure and the failure mode of the tank structure under the final settlement are studied during the two types of uneven settlement.The failure law of the aqueduct body structure under uneven settlement is obtained.