基于可靠度理论的多槽式矩形渡槽优化设计研究

Optimal design of large multi-troughs rectangular aqueduct based on reliability theory

南水北调工程中的大型多槽式预应力矩形渡槽是一种大跨度、大宽度、大高度及大宽高比的新型输水结构,其横向变形不能忽略,在施工、运用过程中将受到比以往小型渡槽更多的不确定因素的影响。首先应用变形相容性原则,考虑了纵向与横向变形的交互影响,然后以结构可靠性指标为约束条件(其中包括性态约束:纵向侧墙的抗弯承载力、跨中挠度、正、斜截面抗裂、整体横向抗风稳定,和适用性约束:输水能力),建立了结构优化数学模型,采用复合型法寻优求解。所得结果为其工程实践提供了理论指导和有价值的参考。

The large pre-stressed multi-troughs rectangular aqueduct in the South-to-North Water Diversion Project is a newly great water conveyance structure,which is characterized by great height,great width,large width-height ratio and large span.Its transversal deformation couldn′t be neglected.In contrast with small-scale aqueduct,this structure is affected by more uncertain factors in construction and operation process.Considering deformation compatibility principle,we take account of the interaction between longitudinal and transversal deformation,and then take reliability indexes as constraints（including performance constraints such as flexural capacity of longitudinal side wall,mid-span deflection,crack resistance of normal and oblique section,anti-wind stability and functional restraint of water conveying capacity） to establish a optimization mathematical model,which is optimized by complex method.The results can provide a useful reference for the construction practice.