提出研究桩土相互作用的新模式──有限层有限元混合法，将半无限空间问题转化为准二维平面问题求解．经理论分析，推导出可解决弹塑性问题的公式．通过实例分析并与三维有限单元分析比较，证实本方法不仅理论清晰、简捷，而且精度较高，运算速度快，应用前景广阔． A new model for studying the interaction between piles and soils is proposed, namely finite layer finite element hybrid method, which transforms the semi-infinite space problem into a quasi-two-dimensional plane problem. After theoretical analysis, the formula that can solve the elastoplastic problem is deduced. Through example analysis and comparison with three-dimensional finite element analysis, it is proved that this method is not only theoretically clear and simple, but also has high accuracy, fast operation speed and wide application prospect.