Abstract: Extended finite element method（XFEM） is a new and effective method for analyzing discontinuity problem arisen in recent few years, specially the problem of fracture. The basic theory of XFEM is introduced and the method of analyzing concrete fracture and crack growth is presented. Finally, the fracturing process of two samples including initial cracks and the crack growth process of the concrete gravity dam are simulated by XFEM. The discipline of displacement and stress field distribution of the samples are analyzed. Comparing with classical finite element method, the crack growth of concrete can be simulated by XFEM without making the crack surface associated to the mesh, without setting dense mesh near the crack tip and without re-meshing after crack growth. Thus the cumbersome works and disadvantages in fracturing analysis are avoided by the application of XFEM. The unique advantage of XFEM in concrete fracturing analysis is displayed.

Key words: XFEM （ Extended Finite Element Method） , concrete , crack growth , numerical simulation ;

摘要： 扩展有限元法(XFEM)是近年来发展起来的分析不连续问题(特别是断裂问题)的一种有效方法。介绍了扩 展有限元法的基本原理,给出了采用扩展有限元法进行混凝土开裂、裂纹扩展分析的方法,最后采用扩展有限元法 模拟了含初始裂纹的混凝土试件和重力坝的开裂扩展过程,分析了其位移、应力场分布规律。算例表明扩展有限 元法在进行断裂分析时克服了常规有限元法的缺点,避免了常规有限元法在分析断裂问题时繁琐的前处理过程, 不需要裂纹面与有限元网格一致,不需要在裂缝周围布置高密度网格,模拟裂纹扩展过程时不需要不断地重新划 分网格,展示了扩展有限元法在裂纹扩展分析中的独特优势。

关键词: 扩展有限元, 混凝土, 裂纹扩展, 数值模拟