桩基梁式多侧墙预应力渡槽体系可靠度研究

Research on System Reliability of Pile Foundation Beam Multi-Lateral Wall Prestressed Aqueduct

对桩基梁式多侧墙预应力大型渡槽工程,以"槽身构件+槽身+支承槽墩+桩基"为研究对象,建立了体系可靠度计算模型,以南水北调中线洺河渡槽为例,计算了不同槽内水深、不同季节输水、不同抗力折减度及不同抗力变异度时,结构体系可靠指标及主要失效模式可靠指标。结果表明:随水深增大,体系可靠度及体系中槽身与桩基的可靠度降减十分明显,遇偶然因素作用引起抗力折减时也出现相似情况;而结构老化引起的体系可靠度降减较为平缓;不同季节输水时体系运行可靠度相差不大;当不考虑桩端承载力时,桩周抗滑稳定可靠度极低。

For the project of pile beam multi-lateral wall prestressed large aqueduct,the paper studied aqueduct components combined with aqueduct,piers support and pile foundation,established system reliability calculation model,with the example of South-to-North Water Diversion Project,calculated the reliability index of the structure system and main failure modes at the conditions of different water depths,seasons,resistance attenuation ratio and resistance mutation degrees.The results show that,with the water depth increases,reliabilities of system and aqueduct body and pile in system cut down very significantly,similar situation arise when encountered the role of causal factors caused resistance reduction;the reliability of the system due to the aging drop minus relatively gentle;system reliability differs not greatly when delivering water in different seasons;without consideration of the end-bearing capacity of pile,anti-sliding stability reliability around the piles is extremely low.