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Evaluation of Ultimate Strength and Deformation Capacity of Pile Foundations Considering Soil-Structure Interaction during Strong Earthquakes

强震时考虑土-结构相互作用的桩基极限强度和变形能力评价

基本信息

批准号：
14350297
负责人：
TOKIMATSU Kohji
金额：
$ 10.11万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

Effects of soil-pile-structure interaction on pile stresses are studied based on large shaking table tests on pile-structure models with and without embedded foundations that are constructed in dry and liquefiable sand deposits. The test results have shown the following :(1)The horizontal subgrade reaction of piles in liquefied soils increases in such a way that the piles are pulled by the soil on the extension side where the reduction of pore pressure occurs. Such mechanism is quite different from that occurring in dry sand where horizontal subgrade reaction is always induced by the increase in earth pressure on the compression side of the pile.(2)If the natural period of the superstructure, T_b, is less than that of the ground, T_g, the ground displacement tend to be in phase with the inertial force from the superstructure, increasing the shear force transmitted to the pile. In contrast, if T_b>T_g, the ground displacement tends to be out of phase with the inertial force, restraining the pile stress from increasing.(3)If soil liquefaction occurs, near surface soil may push the foundation, resulting in an increase in pile stresses. The higher the foundation rigidity, the larger become the pile stresses. The increase in axial force in this case cannot be estimated from the equilibrium of the overturning base moment, as the center of moment equilibrium becomes lower with the development of soil liquefaction.(4)The pile stresses estimated by the pseudo-static analysis, assuming that the maximum moment is equal to the sum of the two stresses caused by the inertial and kinematic effects if T_b<T_g or the squire root of the sum of the squires of the two if T_b>T_g, are in good agreement with the observed ones regardless of the occurrence of soil liquefaction.

基于大型振动台试验，研究了土-桩-结构相互作用对桩应力的影响，对在干燥和可液化砂沉积物中建造的有或没有嵌入基础的桩结构模型进行了研究。试验结果表明：(1)液化土中桩的水平路基反力增大，导致桩在延伸侧受到土体的拉力，孔压减小。这种机制与干砂中发生的机制有很大不同，干砂中的水平路基反作用力总是由桩受压侧土压力的增加引起。(2)如果上部结构的自振周期T_b小于地面的自振周期T_g，则地面位移往往与上部结构的惯性力同相，从而增加了传递到桩的剪力。相反，如果T_b>T_g，地面位移往往与惯性力反相，抑制桩应力的增加。(3)如果土体液化，近地表土可能会推挤地基，导致桩应力增加。基础刚度越高，桩应力越大。这种情况下轴力的增加不能从倾覆基础力矩的平衡来估计，因为随着土体液化的发展，力矩平衡中心变得更低。(4)通过拟静力分析估计的桩应力，假设最大力矩等于惯性和运动效应引起的两个应力之和，如果T_b<T_g或桩的方根之和的方根。如果T_b>T_g，则无论是否发生土壤液化，两个结果都与观测结果非常一致。

项目成果

期刊论文数量（51）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Relationship between displacement and subgrade reaction based on lateral loading tests of steel pipe pile

基于钢管桩侧向荷载试验的位移与路基反力关系

DOI：
发表时间：
2002
期刊：
Journal of Structural and Construction Engineering, AIJ 562
影响因子：
0
作者：
Kohji Tokimatsu;Hiroko Suzuki;Eiichirou Saeki
通讯作者：
Eiichirou Saeki

Influence of inertial and kinematic components on pile response during earthquakes

地震期间惯性和运动分量对桩响应的影响

DOI：
发表时间：
2004
期刊：
Proc., 11th International Conference on soil Dynamics and Earthquake Engineering
影响因子：
0
作者：
Kohji Tokimatsu;Hiroko Suzuki;Masayoshi Sato
通讯作者：
Masayoshi Sato

田村修次: "大型せん断土槽を用いた液状化実験における基礎根入れ部に加わる土圧合力と構造物慣性力の関係"日本建築学会構造系論文集. 559号. 129-134 (2002)

田村修司：“使用大型剪切土罐的液化实验中施加到基础渗透部分的合成土压力与结构惯性力之间的关系”日本建筑学会结构工程学报第 559. 129-134 号（2002 年）。）