高碾压混凝土重力坝功能梯度结构变形协调分析

Deformation coordination analysis of RCC gravity dams with functionally graded structures

高碾压混凝土重力坝中不同功能分区结构界面处往往因材料特性突变而出现破坏与剥离等现象,给工程带来安全隐患。基于新型防渗材料HIAC的特性,在防渗层与主体RCC之间设置过渡层起到辅助防渗及改善分区变形协调的作用,设计了包含矩形、二阶梯、三阶梯三种过渡层的功能梯度结构布置方案,从"变形协调"的角度出发,改变过渡层弹性模量,利用接触理论,分别研究结构整体与材料界面的应力变形规律。结果表明,当过渡层弹性模量高于主体RCC时,坝体中主拉应力处于较低水平;HIAC与RCC法向与切向变形协调状态良好,综合考虑推荐选用三阶梯过渡层,其弹模不宜低于主体RCC。所提出的变形协调分析方法为保证RCC重力坝的精益建造与安全运行提供新的评判手段。

Damage, stripping and other unfavorable phenomena often occur at the interface of a high roller compacted concrete（RCC） gravity dam where exists a mutation in material characteristics, threatening dam safety to a certain degree. In this work, to avoid leakage problems and improve deformation coordination, we arrange a transition layer using new impervious material HIAC between the impervious layer and the main body of RCC dam, and design three schemes of rectangular, two-step and three-step transition for this functionally graded structure. We examine spatial variation in the elastic modulus of the transition layer from the perspective of deformation coordination, and evaluate the stress and deformation in the whole structure and material interface of the dam using the contact analysis theory. Results show that when the elastic modulus of the transition layer is higher than that of the main body RCC, the principal tensile stress in the dam is at a low level and the HIAC and RCC materials are well coordinated in their normal and tangential deformation. The present study recommends the three-step transition structure that should have an elastic modulus not lower than the main body RCC. The concept of deformation coordination developed in this study is useful and would provide a new angle for evaluation of the construction and operation of RCC gravity dams.