The behavior of soil around a pile group was investigated based on a series of dynamic effective stress analyses through the three-dimensional finite element method, simulating centrifuge shaking table tests on soil-pile-structure systems with closely spaced piles reported in a previous study (Suzuki et al., 2006). The computed results show that the mechanism of subgrade reaction in a pile group in dry ground is different from that in saturated ground. The horizontal compression normal stress of the soil at the front side of the pile mainly contributes to the subgrade reaction in dry sand, while pore water pressure reduction at the back side of the pile is the main cause, rather than the normal stress in saturated sand. A series of computed results were found to support the presumed mechanisms of closely spaced pile groups described in a previous experimental study.

基于一系列动态有效应力分析，通过三维有限元方法研究了桩群周围土壤的行为，模拟了先前研究中报道的具有紧密间距桩的土壤-桩-结构系统的离心机振动台试验。铃木等人，2006）。计算结果表明，干地基桩群的路基反应机理与饱和地基不同。桩前侧土的水平压缩正应力主要促成干砂中的路基反应，而桩后侧孔隙水压力降低是主要原因，而不是饱和砂中的正应力.