The soil-pile dynamic interaction mechanism of the large-scale group-piles foundations is of high complexity. Base on the classical variation principle, Las multiplier method and the penalty function method are used to establish the non-linear dynamic interaction analysis model of actual geometric dimensions which can reflect the relative displacement between the pile body and soil body, and the corresponding analytical program is made. With the U-shaped flume engineering in the middle line of the South-to-North water diversion project passing across the Yellow River as the study object, this paper deals with corresponding applicability of the frequently-used M-method in the aqueduct by the model in this paper. The results indicate the under the static loads, the displacement and stress of the superstructure of the aqueduct are basically ,but as to the substructure of the aqueduct ,the results of the M-method are more or less 20% than the results obtained by the non-linear FEM. However, under the earthquake loads, the analysis results by using the non-linear FEM are larger than the M-method, so that effect upon the upper structure of aqueduct is larger than the substructure of aqueduct.%针对大型群桩与土体动力相互作用的高度复杂性,基于经典变分原理,利用拉氏乘子法和罚函数法建立了反映桩体与土体相对运动和其实际几何尺寸的非线性动力相互作用的分析模型,并编制了相应的分析程序.以南水北调中线穿黄U形渡槽工程为研究对象,利用本文的模型研究了常用的M法模型在渡槽结构中应用的适用性.结果表明,在静载作用下,两种方法给出的渡槽上部结构的位移和应力基本一致,渡槽下部桩体结构的分析结果略有差异,但相差不超过20％.在地震荷载下,M法的分析结果是偏小的,尤其是对渡槽上部结构的影响更大.
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