Abstract The geometry of a pile can improve the bearing capacity by changing the load transfer mechanism, such as that of X-section cast-in-place concrete piles (XCC piles). Although the geometrical effects of a single pile and pile group are investigated, the geometrical effects on piled rafts are rarely understood. This paper investigates the geometrical effects on single piles and embedded piled rafts by centrifuge tests and numerical simulations, and non-embedded piled rafts by numerical simulations. The performances of circular single piles, non-embedded and embedded circular piled rafts are included for references. The geometrical effects alter the pile-soil interaction by changing the effective normal stress acting on the pile shaft, causing nonuniform skin friction and considerable side resistance. Compared with that of the circular pile, the advantages of the XCC single pile are mainly contributed by the pile perimeter and weakened by the pile geometry; the advantages of the non-embedded XCC piled raft are mainly determined by the pile perimeter and geometrical effects, which eliminate the group effects; the advantages of the embedded XCC piled raft are mainly contributed by the pile perimeter and geometrical effects, which weaken the group effects and stress concentration and enhance the load sharing on the piles. It is concluded that XCC piles are superior in shaft resistance, especially when used in embedded piled rafts.

中文翻译：

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XCC 桩筏几何效应的离心机和数值模拟

摘要 桩的几何形状可以通过改变荷载传递机制来提高承载力，例如X型截面现浇混凝土桩（XCC桩）。尽管研究了单个桩和桩组的几何效应，但很少了解对桩筏的几何效应。本文通过离心机试验和数值模拟研究了单桩和嵌入式桩筏的几何效应，通过数值模拟研究了非嵌入式桩筏的几何效应。包括圆形单桩、非埋入式和埋入式圆桩筏的性能，供参考。几何效应通过改变作用在桩轴上的有效法向应力来改变桩土相互作用，导致不均匀的皮肤摩擦和相当大的侧阻力。与圆形桩相比，XCC 单桩的优势主要体现在桩周长上，而削弱了桩的几何形状；非嵌入式XCC桩筏的优势主要由桩周和几何效应决定，消除了群效应；嵌入式XCC桩筏的优势主要来自桩周和几何效应，减弱了群效应和应力集中，增强了桩上的荷载分担。得出的结论是，XCC 桩在竖井阻力方面具有优越性，尤其是在用于嵌入式桩筏时。消除群体效应；嵌入式XCC桩筏的优势主要来自桩周和几何效应，减弱了群效应和应力集中，增强了桩上的荷载分担。得出的结论是，XCC 桩在竖井阻力方面具有优越性，尤其是在用于嵌入式桩筏时。消除群体效应；嵌入式XCC桩筏的优势主要来自桩周和几何效应，减弱了群效应和应力集中，增强了桩上的荷载分担。得出的结论是，XCC 桩在竖井阻力方面具有优越性，尤其是在用于嵌入式桩筏时。