波浪荷载下沉箱式防波堤失稳模式及稳定性分析

摘要

As a typical type of breakwater construction, the caisson breakwater has been widely used. Relying on engineering examples, a 3D elastic⁃plastic finite element model based on interaction between caissons structure and foundation was established using ABAQUS finite element software, and the wave load was applied step by step. Two criteria to judge the stability of the structure were proposed according to the structure characteristics of the caisson breakwater. Stability and instability mode analysis methods of the gravity caisson breakwater on sandy soil founda⁃tion were researched. Studies have shown that, within the design wave load, the displacement of the structure was small, and the structure was in elastic state, indicating the structure was stable;the caisson breakwater occurred o⁃verturning under the wave loadings, and the instability mode could be concluded as rotating around a point which was located in the right of central axis under the bottom surface of caisson.%沉箱式防波堤作为一种典型的防波堤结构型式，应用非常广泛。本文依托工程实例，利用ABAQUS有限元软件建立沉箱结构－地基相互作用的三维弹塑性有限元模型，逐级施加波浪荷载，根据沉箱式防波堤的结构特点，提出此种结构稳定性分析的两种判别标准，研究砂土地基上重力式沉箱式防波堤的稳定性与失稳破坏模式分析方法。研究表明：针对本工程，在设计波浪力以内，结构的位移很小，处于弹性状态，结构是稳定的；在波浪荷载作用下沉箱式防波堤发生倾覆破坏，失稳模式为绕沉箱底面以下中轴线偏右某点发生转动失稳。