软土地基沉箱防波堤失稳模式及稳定性分析方法

发布时间：2018-04-02 02:40

本文选题：软黏土地基　切入点：沉箱式防波堤　出处：《海洋工程》2016年03期

【摘要】：针对现阶段深水软黏土地基防波堤建设的设计理论和稳定性分析方法尚不成熟,结合实际工程,采用三维弹塑性有限元数值分析方法,研究在水平或竖直单一方向荷载以及复合加载条件下软黏土地基上沉箱防波堤的失稳模式,提出破坏包络线的稳定性判别方法。在波浪水平荷载作用下,深水软基上沉箱防波堤发生倾覆失稳破坏,失稳转动点为沉箱底面以下中轴线偏右的某点,不同于规范中规定的岩石或砂质地基沉箱倾覆转动点为其后踵点;在重力等竖向荷载作用下,沉箱的失稳模式为结构整体下陷,抛石基床及地基形成连贯的塑性区域,呈现较明显地冲剪破坏形式;在水平、竖向复合荷载作用下,软基上沉箱防波堤的破坏包络线由结构倾覆破坏线和地基承载力破坏线组成,包络线将荷载组合区分成稳定区、仅发生水平承载力不足倾覆破坏区、仅发生地基竖向承载力不足破坏区、同时发生水平承载力和地基竖向承载力不足破坏区4个区域。研究成果为深水软基沉箱防波堤建设提供参考和借鉴。
[Abstract]:Aiming at the immature design theory and stability analysis method of the breakwater construction of deep water soft clay foundation at present, the three-dimensional elastic-plastic finite element numerical analysis method is adopted in combination with practical engineering. The instability mode of caisson breakwater on soft clay foundation under horizontal or vertical single direction load and composite loading is studied, and a method for judging the stability of failure envelope is proposed. The caisson breakwater on soft foundation in deep water is overturned and unstable. The point of unstable rotation is a point on the right of the central axis below the bottom of the caisson, which is different from the heel point of caisson overturning which is stipulated in the code. Under the action of gravity and other vertical loads, the instability mode of caisson is the whole subsidence of the structure, the plastic region of the rubble bed and the foundation forming a coherent plastic zone, and the form of flushing and shearing failure is obvious under horizontal and vertical composite loads. The failure envelope line of caisson breakwater on soft foundation consists of overturning failure line and foundation bearing capacity line. There are only four failure zones in which the vertical bearing capacity of the foundation is insufficient and the horizontal bearing capacity and the vertical bearing capacity of the foundation are insufficient. The research results provide a reference for the construction of the caisson breakwater in the deep water soft foundation.
【作者单位】：天津大学建筑工程学院天津市港口与海岸工程重点实验室;交通运输部天津水运工程科学研究所港口水工建筑技术国家工程实验室水工构造物检测诊断与加固技术交通行业重点实验室;
【基金】：国家自然科学基金项目(51409134) 交通运输部建设科技项目(2014328224040)
【分类号】：U656.2

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