Multiscale Damage Evolution Characteristics and Constitutive Model of Hydraulic Concrete for Drainage Tunnels Under Sulphate Erosion Condition
Corrosive ion-containing groundwater can significantly deteriorate the mechanical properties of concrete in drainage tunnels,thus affecting the safety and stability of water conservancy projects.Using a combination of macro-me-chanical tests and microscopic characterisation tests,this paper investigated the multi-scale deterioration mechanism and mechanical properties of concrete under different erosive fluid concentrations and dry-wet cycle ages,and established a macro and fine damage evolution model under corrosive action.The results show that with the increase of dry-wet cycle age,the compressive strength of concrete decreases linearly,the tensile strength exhibits a rapid decrease followed by a slow decrease,and the modulus of elasticity changes in a similar trend.Under the action of high concentration solution and long-term dry-wet cyclic erosion,the internal porosity and crack size of concrete increased significantly,and the cor-rosion products swelled and reduced the microstructural integrity in a large number of pores and microfissure channels formed by chemical reaction.Based on the experimental results and damage theory,the simulation results of the proposed macroscopic and microscopic damage model have an error of less than 10%,which can characterise the mechanical behav-iour of hydraulic concrete in this environment,and provide a reference for the design of concrete in hydraulic tunnels un-der the water-rich and corrosive environment.
drainage tunnelsulphate erosiondry-wet cyclemulti-scale damageconstitutive model
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