This paper investigates the interference effect of closely spaced foundations on the modulus of subgrade reaction (k) and provides an insight into some of the factors affecting the k-value of a raft foundation when other foundations (isolated footings or other identical rafts) are closely placed on both sides. The investigation adopted a three-dimensional, non-linear, finite-element numerical analysis based on a case study of a residential project with several multi-storey buildings constructed on sand underlain by weathered limestone. A site-specific ground investigation was conducted to determine soil properties, which were used to construct three-dimensional numerical models to simulate different arrangements of foundations and estimate the corresponding k-values. The results show that the k-value starts to decrease when the spacing between the foundations becomes less than three times the raft width, and the percentage of reduction in k-value increases in a non-linear way as the spacing decreases further. In addition to spacing, the study revealed that the effect of adjacent foundations depends on their size and the magnitude of their applied pressure. The case study provides a framework for developing a correction factor that can be applied to k-value for improving the structural and geotechnical design of closely spaced shallow foundations.

中文翻译：

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砂土上密排筏板和孤立地基的路基反应：案例研究

本文研究了紧密间隔的地基对路基反应模量 ( k ) 的干扰影响，并深入了解了当其他地基（隔离基础或其他相同的筏板）靠近时影响筏板基础k值的一些因素放在两侧。该调查采用了三维、非线性、有限元数值分析，该分析基于一个住宅项目的案例研究，该项目在风化石灰岩下的沙子上建造了几栋多层建筑。进行了特定地点的地面调查以确定土壤特性，这些特性用于构建三维数值模型以模拟不同的地基布置并估算相应的k-价值观。结果表明，当基础间距小于筏板宽度的3倍时，k值开始减小，且随着间距进一步减小， k值减小的百分比呈非线性增加。除间距外，该研究还表明，相邻地基的影响还取决于它们的大小和所施加压力的大小。该案例研究提供了一个框架，用于开发可应用于k值的校正因子，以改进紧密间隔的浅基础的结构和岩土工程设计。