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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.

通过大型振动台试验，研究了在干燥可液化砂土中建造的有预埋基础和无预埋基础的桩-结构模型中土-桩-结构相互作用对桩应力的影响。试验结果表明：(1)液化土中桩的水平路基反力增大，桩受到延伸侧土体的拉拔，孔压减小。这种机制与干砂条件下水平路基反力的发生机制有很大不同，干砂条件下水平路基反力通常是由桩受压侧土压力的增加引起的。(2)当上部结构的自然周期T_b小于地基的自然周期T_g时，地基位移与上部结构的惯性力趋于同相，传递给桩的剪力增大。而当T_b>T_g时，地面位移与惯性力趋于非相，抑制了桩应力的增大。(3)如果发生土壤液化，近表层土壤可能会推动基础，导致桩应力增大。基础刚度越高，桩应力越大。在这种情况下，轴向力的增加不能从倾覆基础弯矩的平衡来估计，因为随着土壤液化的发展，弯矩平衡中心变得更低。(4)当T_b<T_g时，假设最大弯矩等于惯性和运动作用引起的两个应力之和；当T_b>T_g时，假设最大弯矩等于这两个应力之和的平方和的平方根，拟静力分析估计的桩应力与观测值吻合较好。

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）。）