现有的结构-地基动力相互作用分析方法很难同时模拟地基的无限特性和非均质特性。基于比例边界有限元方法（Scaled Boundary Finite Element Method，简称SBFEM），充分发挥其能够模拟延伸至无限远的复合材料，但不用离散材料之间的交界面的优点，主要分析了无限地基中断层对混凝土重力坝、拱坝的地震响应的影响。结果表明，断层的存在会对大坝的地震响应产生不同程度的影响，能够引起应力的重分布甚至严重的应力局部集中，所以在大坝抗震设计中和抗震安全评价中应该引起足够重视。

Current methods cannot simulate the infinite property and complexity of the heterogeneous foundation synchronously. In this paper, the concrete dam and the unbounded foundation were simulated by the scaled boundary finite element method (SBFEM). The remarkable advantage of this method is that it can reflect the infinite behavior of the foundation exactly. The most important is that no additional computational effort is needed when simulating the faults in the foundation. The study result shows that the existence of faults would generate an influence on seismic response in different extents, and cause the redistribution of earthquake stresses, even stresses to be concentrated partially. So the effect of the presence of faults should be taken into consideration.