The present paper investigates the behaviour of circular shallow footings on soft clay soils with skirted and non-skirted sand piles. The main goal of this study is to evaluate the settlement and bearing capacity of a circular foundation, which is placed on a soft clay layer, based on a sandy soil layer. Different piles with varying length to clay layer thickness ratios ranging from 0.25 to 1 were modelled experimentally, as well as numerically, both with and without skirt. The effects of using a steel skirt and the length to clay layer thickness ratio of the piles, compared to the case in which the footing is placed on a pile without any skirt, and in the case of a shallow foundation without piles, were also investigated in this study. A model generated by finite element software was also used for numerical analysis. The results indicate that the use of skirted piles can affect the load–settlement curves and increase the bearing capacity. By increasing the ratio of pile length to clay thickness, the bearing capacity of the shallow foundation will be increased and the corresponding settlement will be decreased. Therefore, the bearing capacity failure mechanism of a footing resting on soft clay can be modified from the punching failure to the general shear failure at the tip of the confined replaced sand column. Load–settlement diagrams and bearing capacity obtained by numerical results are in accordance with the results derived from experimental observations.

中文翻译：

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带裙边沙桩与不带裙边砂桩层状土圆形基础承载力试验及数值研究

本文研究了圆形浅基脚在具有裙边和非裙边砂桩的软粘土上的行为。本研究的主要目标是评估圆形地基的沉降和承载能力，圆形地基放置在软粘土层上，基于沙土层。不同长度与粘土层厚度比范围从 0.25 到 1 的不同桩通过实验和数值模拟，有和没有裙边。还研究了使用钢裙边和桩的长度与粘土层厚度比的影响，与将基础放置在没有裙边的桩上的情况相比，以及在没有桩的浅基础的情况下，还进行了研究在这个研究中。有限元软件生成的模型也用于数值分析。结果表明，裙桩的使用可以影响荷载-沉降曲线并增加承载力。通过增加桩长与黏土厚度的比值，浅地基的承载力会增加，相应的沉降会减少。因此，软粘土基脚的承载力破坏机制可以从冲孔破坏转变为密闭置换砂柱尖端的一般剪切破坏。数值结果得到的荷载沉降图和承载力与实验观测结果一致。浅基础的承载力会增加，相应的沉降会减少。因此，软粘土基脚的承载力破坏机制可以从冲孔破坏转变为密闭置换砂柱尖端的一般剪切破坏。数值结果得到的荷载沉降图和承载力与实验观测结果一致。浅基础的承载力会增加，相应的沉降会减少。因此，软粘土基脚的承载力破坏机制可以从冲孔破坏转变为密闭置换砂柱尖端的一般剪切破坏。数值结果得到的荷载沉降图和承载力与实验观测结果一致。