Mechanical behavior and parameter sensitivity analysis of water supply steel pipes under complex service load combinations

• Published in: Structures (Oxford) 2024-09, Vol.67, p.106956, Article 106956
• Main Authors: Ma, Ying, Li, Bin, Fang, Hongyuan, Du, Xueming, Wang, Niannian, Zang, Quansheng, Zhai, Kejie, Di, Danyang
• Format: Article
• Language: English
• Subjects: Mechanical behavior; Model box test; Rehabilitation; Sensitivity analysis; Service load combinations; Water supply pipes
• ISSN: 2352-0124; 2352-0124
• DOI: 10.1016/j.istruc.2024.106956

Underground water supply pipelines are critical lifelines for cities, operating in complex environments and varying operational conditions. The complex mechanical behaviors under various service loads such as soil cover, traffic, groundwater, and internal pressure have not yet been fully investigated. This research develops a structural model of steel pipe-soil stress and seepage interaction using ABAQUS 6.14–1, alongside an internal pressurized fluid model in FLUENT. Through the innovative utilization of the MpCCI (Mesh-based parallel Code Coupling Interface) multi-physics coupling platform, coupling solutions of the structural and pressurized fluid models were achieved in both temporal and spatial scales. Validation of numerical results was conducted through a full-scale model box test observation. The impacts of different load combinations on the longitudinal and circumferential stress values and distributions in the steel pipe, and the vertical displacement at the crown were initially investigated. Furthermore, parametric and sensitivity analyses of factors including internal pressure, traffic load, groundwater level, burial depth, vehicle speed, and flow velocity on the longitudinal and circumferential stresses of the pipe were performed. The findings indicate that the load combinations with the most significant influence on the stress and vertical displacement of steel pipes are respectively burial depth + internal pressure + traffic load and burial depth + internal pressure + groundwater, with their respective maximum stress and vertical displacement being 15.91 MPa and 1.82 mm. When the six factors shifted from the minimum to the maximum design values, the maximum steel pipe stress increased by 220.1 %, 53.2 %, and 12.7 % respectively with the rise of internal pressure, traffic load, and burial depth. Conversely, when the groundwater level rises, the maximum steel pipe stress decreased by 8.3 %, and the vertical displacement of the pipe increased by 154 %. The impact of vehicle speed and flow velocity on the maximum steel pipe stress is less than 0.7 %. The Morris method categorizes the 6 factors into 3 levels: internal pressure and burial depth are sensitivity parameters; the magnitude of traffic loading and groundwater height are medium sensitivity parameters; vehicle speed and flow velocity are classified as insensitive parameters.