权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study of Ultimate Lateral Load-capacity of Pile Groups under Axial and Lateral Forces

轴、侧向力作用下群桩极限侧向承载力研究

基本信息

批准号：
61550413
负责人：
TOMINAGA KOJI.
金额：
$ 1.02万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550413/
关键词：
Interaction of Pile and Soil Effect of Pile Groups Ultimate Lateral-Load Capacity Ductility of Pile Foundation Additional Moment アーチ効果群抗効果鉛直力による付加曲げアー4効果保有水平耐力群杭の相互作用鉛直と水平の合成力

项目摘要

The results and informations obtained from theoretical and experimental studies on the lateral behavior of pile group foundations up to failure under combined load can be summarized as follows.1. In order to apply simultaneously both axial and lateral forces at the cap of pile group foundation, the apparatus having the lateral moveng container on two rails was developed. the accuracies of conditions during all tests carried out were examined.2. Group efficiency due to the interaction of piles gradually decreases as the pile spacing, R, increases. For R=2D(D:pile diameter), however, it is observed that the behavior deffers from others because of arch-action in sand. Furthermore, it is indicated that at the ultimate state of pile group foundations the deflection decreases and the lateral resistance increases as R increases.3. In general, it is found that the group reduction factor decreases with increasing numbers of piles in a group, and increase in number leads to increase in ductility of pile group foundations.4. For the pile groups subjected to vertical load, the lateral load-deflection curves have a peak, and the ultimate lateral resistance is reduced because of the additional moment caused by deflection, as compared the results without vertical force.5. The analytical method, in which the method of incremental displacement is used to predict the nonlinear behavior up to failure due to yielding of soil and pile, is predicted. Comparisons between the observed and predicted load-deflection behavior are made. It is found that the agreement between predicted and observed curves is reasonable for single piles and pile groups at large spacings, but the theory overpredicts movements and underpredicts ultimate lateral resistances for pile groups at close spacings.

本文对群桩基础在复合荷载作用下的侧向性状进行了理论分析和试验研究，得到了以下结果和信息：1.为了同时对群桩基础承台施加轴力和侧向力，研制了一种在两条轨道上横向移动容器的装置。对所有试验过程中条件的准确性进行了检查。由于桩的相互作用，群效率随着桩间距R的增加而逐渐减小。当R=2D（D：桩径）时，由于砂土中的拱效应，桩的受力性能与其它桩的受力性能不同。研究表明，群桩基础极限状态下，随着R的增大，群桩基础的挠度减小，侧阻力增大.总体而言，群桩基础的群桩折减系数随着群桩个数的增加而减小，群桩个数的增加会导致群桩基础延性的增加.竖向荷载作用下群桩的荷载-挠度曲线出现峰值，与无竖向荷载作用时相比，由于挠度引起的附加弯矩，群桩的极限侧阻力减小.采用增量位移法预测桩土屈服破坏前的非线性性状。观察到的和预测的载荷-挠度行为之间的比较。结果表明，对于大间距的单桩和群桩，理论预测曲线与实测曲线吻合较好，但对于小间距的群桩，理论高估了群桩的位移，低估了群桩的极限侧阻力。