Research on Health Evaluation Method of Single Ring Segment of Subway Shield Tunnel Under Multi-Defect Coupling
The traditional single-ring segment health evaluation method does not consider the effect of multi-defect coupling on structural performance,which may lead to optimistic evaluation results.In this paper,based on the defects statistics of a city subway,the main types and internal correlations of urban subway defects are discussed.With the help of numerical simulation,the bearing capacity prediction model and health evaluation method of single ring segment considering defect coupling are proposed,and its rationality is verified by field application.The main conclusions are as follows:(1)Water leakage,misalignment,cracking,structural deterioration(corrosion,spalling,etc.)and tunnel deformation are the main types of urban subway defects,which are closely related,and the service performance of the structure is affected by the coupling of multiple defects;(2)There are differences in the evolution of bearing performance,damage characteristics and sensitivity to various defects of segment lining affected by different types of defect coupling under loading conditions;(3)Based on the steel bar section loss rate α,crack depth to segment thickness ratio β,spalling area depth to segment thickness ratio γ,cavity range behind m,the bearing capacity prediction model and health evaluation method of single ring segment are established respectively,which are categorized into four coupling types of steel rust-segment cracking,steel rust-spalling falling block,hollow behind segment cracking,segment cracking and spalling falling block.
subwayshield tunnelsegmenthealth degree classificationfinite element analysisprediction modelbearing capacity
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