DDA与FEM耦合法在分缝重力坝非线性分析中的应用

DDA coupled FEM and its application in concrete gravity dams with joints

混凝土重力坝一般设有数条纵缝。纵缝使坝体的连续性遭到破坏,一般的有限单元法很难处理这样的不连续变形问题。本文首先阐述了DDA(DiscontinuousDeformationAnalysis)与FEM(FiniteElementMethod)耦合算法的原理,然后采用作者自行研制的DDA与FEM耦合法程序对一实际重力坝进行了详细的计算分析。重点讨论了纵缝的不同设置形式和缝宽大小对坝体变形和应力分布、坝底面接触应力分布以及坝基面应力分布的影响,为工程设计提供依据。

Concrete gravity dams are constructed with multiple longitudinal joints. In order to avoid excessive stresses convergence, bended joints are designed at the top of longitudinal joints. Because of the existence of longitudinal joints the deformations of the dams become discontinuous and it is difficult to compute such deformations using conventional Finite Element Method (FEM). In this paper, the Discontinuous Deformation Analysis (DDA) coupled with FEM is proposed. Using the program developed by the authors, a concrete gravity dam with multiple longitudinal joints is computed in detail. Different longitudinal joint shape and gap size are considered in the effects on the deformations and the stress distributions in the dam. From the results, two conclusions can be obtained: (1) DDA coupled with FEM enhances the ability of modeling block's deformation and stress distribution filed; (2) The deformations and the stresses in the dam with the bended joints are smaller than those with straight joints, so it is better to design concrete gravity dam with bended joints.