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

本研究的主要目标是 1) 为桩筏基础设计提供承受静态水平荷载和动态（地震）荷载的桩筏综合实验数据，2) 开发一种简单但可行的桩变形和荷载比例分析方法为了实现这些目标，对桩筏进行了一系列离心建模，得出了以下一些结论： 1．在评估桩筏设计中桩的响应以及桩之间的相互作用效应时，应考虑由于通过筏底座传递的荷载而引起的桩周围围压的增加。 2. 与筏垂直荷载和系数的估计相比，桩中筏组件的极限摩擦阻力较小（刚性桩头连接）或几乎相同（铰接桩头连接）筏板底座与筏板之间的摩擦力认为筏板下方土体受到桩的约束，可以减少筏板底部土体的剪切变形，从而使界面处的动员剪应力较小。3．各构件承受的水平荷载中，筏板最初承载的荷载大于桩，在刚性桩头连接的桩筏中，桩的位移大于筏板。在铰接桩头连接的桩筏中，桩的贡献为桩很多然而，总体而言，该比例很大程度上取决于桩筏位移，因此在桩筏基础的设计中考虑这种非线性响应非常重要。4。沉降、水平位移和倾斜）以及构件所承载的荷载比例是最重要的因素，本文对上述因素的动力行为进行了深入研究。5．而且筏基相对较小即使当桩筏受到相对较强的输入运动时，水平载荷也较小。