水位循环变化作用下有纵缝重力坝的非线性特性

The Study on Nonlinear Characteristics of Concrete Gravity Dam with Longitudinal Joints Subjected to Cyclic Loading due to Water Level Fluctuation

在简述了笔者所发展的一种新的多体系统非连续变形分析方法的基础上 ,应用这一模型进行了具体数值计算 ,探讨了有纵缝重力坝在水位循环变化作用下的应力与变形特性。数值分析表明 ,在库水位循环变化等复杂加载历史作用下 ,坝体的变形、主应力大小及其方向角和缝间界面接触应力呈现非线性的周期性变化 ;当纵缝为连续接触时整个坝体的应力与变形呈现出线性特性 ,而当纵缝为非连续接触且具有缝宽时 ,系统表现出强烈的非线性特性 ,随着缝宽的增大非线性程度降低 ,但坝体的应力集中效应加剧。算例研究表明本文方法为有缝结构的非线性分析和接触分析提供了有力的计算工具。

In this paper, the new numerical analysis method for the discontinuous deformation system consisting of multiple rigid or elastic bodies developed by the authors is presented. Then it is applied to analyze nonlinear behavior of concrete gravity dam with multiple longitudinal joints subjected to cyclic loading history due to the fluctuation of reservoir water level. Through numerical computations it is found that the model can reasonably predict both deformations, principal stresses together with their directions in the dam body and contact stresses or forces and relative displacements along the longitudinal joints and the dam base interface. When the longitudinal joints are continuous, the dam system will behave elastically. However, when the longitudinal joints are discontinuous contact surfaces, the dam will display nonlinear characteristics. With increase of the width of longitudinal joints, nonlinear effect will be reduced but the degree of stress concentration will be risen. It has been shown that the proposed method is powerful and practically applicable for evaluation complex behavior of the multi body interaction system including discontinuous deformation characteristics.