全级配大坝混凝土裂缝开展机理及失稳扩展特性研究

项目名称： 全级配大坝混凝土裂缝开展机理及失稳扩展特性研究

项目编号： No.51269007

项目类型： 地区科学基金项目

立项/批准年度： 2013

项目学科： 水利工程

项目作者： 武亮

作者单位： 昆明理工大学

项目金额： 50万元

中文摘要： 由于混凝土大坝的重要性，大坝裂缝问题一直是各国水电建设中的重大研究课题。一般材料断裂特性的研究都是要建立在大量试验基础上的，但限于实验手段和设备要求，要获得充分的全级配大坝混凝土断裂力学特性是很困难的。不同于一般脆性材料，混凝土断裂伴随着相对较大范围的断裂过程区的出现，使得线弹性断裂力学不能直接应用，其断裂特性表现为非线性行为。本项目以现场试验和室内试验为基础，借助反演数值分析计算，围绕混凝土断裂过程区的微细观构成和宏观特性，从细观层面上建立材料单元损伤本构关系，揭示裂纹发生发展的内在机理及演变规律，从宏观层面上建立混凝土断裂过程区非线性软化本构关系，并通过对实验室小试件尺度效应的分析研究，提出能满足大坝断裂分析计算所需的配套室内实验方法。利用细观分析的裂面剪切强度和分形研究的裂面几何性态，研究裂面剪切位移与法向位移的内在关系，建立混合断裂模式下的断裂准则，从而揭示出裂缝扩展演化规律。

中文关键词： 混凝土；断裂；细观模型；参数识别；软化曲线

英文摘要： The problem of concrete dam cracks has been a major topic in hydropower construction in the world due to the importance of dam safety. In general, many experiments must be done to research on the fracture characteristics of materials. However, it is very difficult to get a lot of information about the fracture properties of fully-graded aggregate dam concrete because of requiring some special experimental procedure. Unlike brittle material, the deviation of the fracture behavior of concrete from LEFM is existence of fracture process zone that is not small enough compared to the structure dimensions. In this project, some inverse analysis will be completed around the microstructure and macroscopic behavior of the fracture process zone in concrete fracture, based upon in-situ tests and laboratory experiments. A damage constitutive formulation will be constructed at a mesoscopic level in order to exposit the internal mechanism and evolution law and a stress-displacement law that exhibits softening in the fracture process zone will be presented at a macroscopic level. The relationship between the shear displacement and the normal displacement on the crack surface will be explored by making use of the shear strength on crack surface obtained from mesoscopic analysis and the geometric properties of cracks through frac

英文关键词： concrete；fracture；mesoscale model；parameter identification；softening curve