A series of laboratory tests was conducted to measure the vertical and horizontal displacement responses of pile foundations when subjected to dynamic loads. Eight tests were conducted on a single pile in dry soil at a relative density (RD) of 30% (loose) or 50% (medium); 66 tests on groups of piles with different spacings and patterns in dry soil at RD 30% and 50% were also performed. All the tests were carried out at operating frequencies of 0.5, 1 and 2 Hz under horizontal shaking and all considered one embedment ratio (L/d = 30). The tests were grouped in terms of the number of piles (two, three and four piles in row and line patterns) and three pile spacing ratios (s/d = 3, 4 and 5). The vibration box used in this work was able to simulate accurately earthquake motion induced on foundations and pile groups. An increase in shaking frequency led to a reduction in the oscillation of wave propagation values recorded due to densification of the soil during shaking. The pile spacing was found to be an important parameter that affects the time–frequency characteristics of displacement at the pile top. With an increasing in the pile spacing ratio s/d, the internal forces were slightly reduced.

中文翻译：

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水平激励下干土中模型桩的竖向和水平位移

进行了一系列的实验室测试，以测量承受动态载荷时桩基的垂直和水平位移响应。在干燥土壤中的单桩上进行了八项测试，相对密度（RD）为30％（松散）或50％（中等）。还对RD为30％和50％的干燥土壤中不同间距和样式的桩组进行了66次试验。所有测试均在水平振动下以0.5、1和2 Hz的工作频率进行，所有测试均考虑为一种嵌入率（L / d  = 30）。根据桩的数量（行和线型的两个，三个和四个桩）和三个桩的间距比（s / d）对测试进行分组。 = 3、4和5）。在这项工作中使用的振动箱能够准确模拟在基础和桩群上引起的地震运动。摇动频率的增加导致由于摇动过程中土壤的致密化而导致记录的波传播值的振荡减少。发现桩距是影响桩顶位移时频特性的重要参数。随着桩间距比s / d的增加，内力略有减小。