基于连续-非连续方法的混凝土面板堆石坝面板开裂机理研究

Concrete face rockfill dam is one of the most promising type dam constructions. With the development of the dam construction technology, the concrete face rockfill dam is being built higher and higher, and the size of the project is larger and larger, the core problem of the construction of ultrahigh(300 m grade) dam is the cracking prevention of panel. Therefore, establishing a reasonable numerical calculation model of continuous - discontinuous about the cracking of the concrete panel, and analyzing the cracking mechanism of panel has important scientific significance and possess the value of practical application. The project is on the basis of mastering the characteristics of cracking of concrete face rockfill dam; utilizing the partition of unity characteristics of element shape function and finite element enrichment technology, conforming discontinuous approximate function of elements with cracks, establishing a continuous - discontinuous calculation model about the cracking; using the model, and considering the long-term deformation of the dam which is caused by rheological deformation, wetting deformation and cyclic loading and unloading deformation of rockfills, conducting the numerical simulation on the cracking of concrete face rockfill dam; analyzing the cracking process of the concrete panel, revealing the cracking mechanism,and proposing reasonable measures of cracking prevention. It is important for the research of this project to reveal the initiation, expanding and until the occurrence of cracking damage law of concrete panel cracks, and provides a theoretical basis and technical support for design, construction and operation management of the ultrahigh concrete face rockfill dam.

混凝土面板堆石坝是目前坝工建设中最具发展前景的坝型之一。随着筑坝技术的发展，面板堆石坝越建越高、工程规模越来越大，面板防裂是建设超高（300 m 级）混凝土面板堆石坝的关键技术问题。因此，建立合理的混凝土面板开裂数值计算模型，揭示面板的开裂机理具有重要科学意义和实际应用价值。本项目在掌握混凝土面板堆石坝面板开裂特征的基础上，利用有限元富集技术与单元形函数的单位分解特性，构造单元内含有裂缝的非连续近似函数，建立面板开裂的连续-非连续数值计算模型。采用该模型，考虑由堆石体流变变形、湿化变形、循环加卸载变形引起的坝体长期变形，进行面板堆石坝数值仿真计算，研究分析混凝土面板的开裂过程，揭示面板的开裂机理，并提出合理的防裂措施。本研究项目对于揭示混凝土面板裂缝萌生、扩展直至发生开裂破坏的机理有重要意义，可以为超高混凝土面板堆石坝的坝体变形控制和面板防裂提供理论基础与技术支撑。

混凝土面板堆石坝是目前坝工建设中最具发展前景的坝型之一。随着筑坝技术的发展，面板堆石坝越建越高、工程规模越来越大，面板防裂已成为建设超高混凝土面板堆石坝的关键技术问题。因此，建立合理的混凝土面板开裂数值计算模型，揭示面板的开裂机理具有重要科学意义和实际应用价值。.本研究考虑堆石体的流变和湿化变形作为长期影响因素，进行了相应的有限元数值仿真分析，研究分析长期变形作用下混凝土面板堆石坝的应力变形特性；研究表明，考虑堆石体的长期变形之后，坝体的位移及大、小主应力的极值均有不同程度的增加，对大坝安全有着不可忽视的影响，需要为堆石体的长期变形预留一定的沉降量。基于堆石体的长期变形特性，研究了库水位循环升降作用下的堆石体应力变形；而将库水位循环升降作为考虑因素之后，计算分析结果表明，随着库水位升降次数的增加，坝体的位移和和大小主应力的变化均随之增大，特别是面板的挠度受其影响较大。随后通过对面板堆石坝工程实例调研，研究混凝土面板的结构特征，并以此为基础，分析混凝土面板开裂机理及破坏过程；该研究基于扩展有限元法，利用有限元富集技术与单元形函数的单位分解特性，构造单元内含有裂缝的非连续近似函数，对ABAQSU进行二次开发，建立了面板开裂的连续-非连续数值计算模型。.本研究项目对于揭示混凝土面板裂缝萌生、扩展直至发生开裂破坏的机理有重要意义，可以为超高混凝土面板堆石坝的坝体变形控制和面板防裂提供理论基础与技术支撑。