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Behavior of piled raft foundations subjected to static horizontal loading and seismic loading

桩筏基础在静水平荷载和地震荷载作用下的性能

基本信息

批准号：
12450188
负责人：
MATSUMOTO Tatsunori
金额：
$ 7.04万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450188/
关键词：
Piled raft Pile Centrifuge modeling Laboratory model test Horizontal resistance Earthquake-proof Sand Deformation analysis

项目摘要

The main objectives of this research are 1) provide comprehensive experimental data for pile rafts subjected to static horizontal loads and dynamic (seismic) loads for design of piled raft foundations, 2) develop a simple but workable analytical method for deformation and load proportion of pile rafts and pile groups. To achieve these objectives, a series of centrifuge modeling of pile rafts was extensively conducted and some conclusions are shown below:1. The stiffness and the ultimate resistance of the single pile in the piled raft are highly different from those observed in the loading test of the isolated single pile. The increase in the confining stress around the pile due to the load transferred through the raft base should be considered in the evaluation of the pile response in the piled raft design, as well as the interaction effects between the components.2. The ultimate frictional resistance of the raft component in the piled raft was smaller (rigid pile head connection) or a … More lmost the same (hinged pile head connection) compared with the estimates from the raft vertical loads and the coefficient of the friction between the raft base and the soil. It was thought that the soil beneath the raft was constrained by the piles which may reduce the shear deformation of the soil just beneath the raft base, and thus the mobilized shear stress at the interface was smaller.3. As for the proportion of the horizontal load carried by each component, the raft initially carried more load than the piles, with larger displacements the piles more than the raft in the piled raft with rigid pile head connection. In the piled raft with hinged pile head connection, the contribution of the piles was much smaller. Overall, however, the proportion is highly dependent on the piled raft displacement, and it is therefore important to consider such non-linear response in the designs of piled raft foundations.4. In the piled raft designs, evaluation of the displacement (settlement, horizontal displacement, and inclination) and the proportion of the load carried by the components are the most important factors. The dynamic behaviors of the above factors were intensively examined in this paper.5. The change in the vertical load sharing between the piles and the raft base was relatively small compared with the horizontal load, even when the piled rafts were subjected to relatively strong input motion. Less

本文研究的主要目的是：1）为桩筏基础设计提供桩筏基础在水平静荷载和动力（地震）荷载作用下的试验数据; 2）建立桩筏基础和群桩基础的变形和荷载分担的简单实用的分析方法。为实现上述目标，本文对桩筏基础进行了大量的离心模型试验，并取得了以下主要结论：1。桩筏基础中单桩的刚度和极限承载力与单桩静载荷试验结果有很大差异。在桩筏基础设计中，在计算桩的响应时，应考虑荷载通过筏板传递而引起的桩周围压的增加，以及各构件之间的相互作用.桩筏板中筏板构件的极限摩阻力较小（刚性桩头连接）， ...更多信息 lmost相同（铰接桩头连接）与筏板垂直荷载和筏板基础与土壤之间摩擦系数的估计值相比。研究认为，桩对筏板下土体的约束作用可以减小筏板下土体的剪切变形，从而使接触面处的动剪应力较小.在桩端刚性连接的桩筏基础中，从各构件所承担的水平荷载比例来看，筏板的初始荷载大于桩，随着桩端位移的增大，桩的初始荷载大于筏板。在桩头铰接的桩筏基础中，桩的贡献要小得多。但总的来说，这一比例与桩筏基础的位移密切相关，因此在桩筏基础设计中考虑这种非线性响应是非常重要的.在桩筏基础设计中，位移（沉降、水平位移和倾斜）的计算和各构件所承担的荷载比例是最重要的因素。本文对上述因素的动力学行为进行了深入的研究.与水平荷载相比，桩筏基础之间的垂直荷载分配变化相对较小，即使桩筏受到相对较强的输入运动。少