Influence mechanism of vertical-horizontal combined loads on the response of a single pile in sand
Influence mechanism of vertical-horizontal combined loads on the response of a single pile in sand
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DOI：
10.1016/j.sandf.2018.07.002
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发表时间：
2018-10-01
影响因子：
3.7
通讯作者：
Zhang, Ga
中科院分区：
文献类型：
--
作者：
Lu, Wenjun;Zhang, Ga
在许多岩土工程中，如沿海和近海工程，桩基用于支撑垂直和水平荷载。在目前的设计实践中，对桩在竖向水平组合荷载作用下的响应进行了分别分析和叠加。这种简化的分析方法没有考虑组合荷载的耦合效应。关于这一课题的研究是有限的，迄今为止报道的结果对于竖向荷载对桩的水平响应的影响尚无定论。本文通过一系列离心模型试验，研究了不同竖向-水平组合荷载条件下组合荷载对砂土中桩基响应的影响规律及机理。竖向荷载使桩附近的土体变密，从而使桩的水平位移和弯矩减小，这被称为“土体致密效应”。由于桩的侧向变形，竖向荷载引起桩的附加弯矩：这被称为“p - δ效应”。在水平加载初期，土壤致密化效应起主导作用，p - δ效应随着水平加载的增加而增强。这两种看似相反的作用的复合效应是随着水平荷载的增大，桩的弯矩减小先减小后增大。桩的附加沉降主要由水平荷载引起，且与前竖向荷载呈正相关。(C) 2018年由Elsevier B.V.代表日本岩土学会制作和主办。
Pile foundations are used to support both vertical and horizontal loads in many geotechnical projects, such as the coastal and offshore engineering. The responses of piles under vertical-horizontal combined loading are separately analyzed and then superposed in current design practice. This simplified analysis approach does not take the coupling effect of the combined loads into consideration. The research on this topic is limited and the results reported to date are inconclusive with regard to the influence of vertical loads on the horizontal response of piles. In this paper, a series of centrifuge model tests under different vertical-horizontal combined loading conditions was performed to investigate the influence rules and mechanism of the combined loads on the response of piles in sand. The vertical load is shown to densify the soil near the pile and therefore decrease the horizontal displacement and bending moment of the pile: this is termed the "soil densification effect". The vertical load induces an additional bending moment of the pile due to the lateral deformation of the pile: this is termed the "P-Delta effect". The soil densification effect plays a dominant role in the early horizontal loading while the P-Delta effect is strengthened as the horizontal loads increases. These compound effect of these two seemingly opposing effects is a decrease in the bending moment of the pile decrease first then increase as the horizontal load increases. Additional settlement of the pile is caused by horizontal loading and isa positively correlated with the pre-vertical loads. (C) 2018 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society.