The Development of Consitutive Equation under General Stress Condition for Sands Anisotropic Deformation-Failure Behaviors due to Initial Structure and Stress History

初始结构和应力历史引起的砂土各向异性变形破坏行为一般应力条件下本构方程的展开

• 批准号: 63550355
• 负责人: TOKI Shosuke
• 金额: $ 1.34万
• 依托单位: Hokkaido 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: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550355/
• 关键词: Sand; Constitutive equation; Deformation-strength characteristics; Anisotropy of intial structure; Shear stress history; Confinig stress dependency; Finite element method; Bearing capacity of ground; 構造異方性; 応力履歴; 拘束圧依在性

The results of the research during two years are sunmmarized as follows :1. The constitutive model for three-dimensional deformation-failure behaviors of sands was developed. The model is named 'Multi-Directional Slinding Model'.(a) The basic soncept of the model is that granular materials such as sands are essentially descrete and have innumerable potential sliding planes in all locations and in all directions, and its deformation characteristics are governed by the slidin13EA\ : g mechanisma on each sliding plane.(b) Theree types of deformation mechanisms are considered on each sliding plane : compression, shear deformation and dilatancy.(c) The values of model parameters can be determined from the deformation behabiors observed in conventional triaxial tests.2. The model was applied to various stress conditions, and was verified by the observed deformation-failure behaviors.(a) The model is applicable to the general stress conditions including the rotation of stress axs, and can take the effects of confining pressure and overconsolidation into account.(b) The model can siulate the inherent and induced anisotropies in sands deformation-failure behaviors : the former is due to the anisotropic initial structures formed by sand grains and the latter is due to the shear stress history.3. The model was incorporated to the finite element method for boundary value problem. The calculation method is applied to the bearing capacity probles of shallow footing.(a) It was found that the model can predict the load-displacement behaviors and deformation properties of graound with initial anisotropic structures.(b) The scale effect of footing width on bearing capacity was predicted propwerly by the calculation method, becouse the effect of confining pressure on shear strength of sand element is taken into account by the model.

本研究历时两年，主要研究成果如下：1.建立了砂土三维变形破坏特性的本构模型。该模型被命名为“多方向滑移模型”。(a)该模型的基本思想是：砂土等散粒体材料本质上是离散的，在各个位置和各个方向上都有无数个潜在的滑动面，其变形特性受每个滑动面上的滑动机制控制。(b)在每个滑动面上考虑了三种变形机制：压缩变形、剪切变形和剪切变形。(c)模型参数的取值可根据常规三轴试验中观测到的变形特征确定.将该模型应用于各种应力条件下，并通过观察到的变形破坏行为进行了验证。(a)该模型适用于包括应力轴旋转在内的一般应力条件，并能考虑围压和超固结的影响。(b)该模型可以模拟砂土变形破坏行为中的固有各向异性和诱导各向异性：前者是由砂粒形成的各向异性初始结构引起的，后者是由剪应力历史引起的.将该模型应用于有限元边值问题求解。将该计算方法应用于浅基础承载力问题。(a)结果表明，该模型能够较好地预测具有初始各向异性结构的颗粒的荷载-位移特性和变形特性。(b)该模型考虑了围压对砂体抗剪强度的影响，较好地预测了基础宽度对承载力的尺度效应。

项目成果

K.Miura, S.Toki and W.D.L.Finn: "Three-Dimensional Consititutive Model For Sand -Derivation of Multi-Directional Sliding Model- (in Japanese)" Bulletin of the Faculty of Engineering, Hokkaido University. No.140. 1-13 (1988)

K.Miura、S.Toki 和 W.D.L.Finn：“砂的三维本构模型 - 多向滑动模型的推导 -（日语）” 北海道大学工学部通报。

K.Miura, K.Ueno, S.Toki and W.D.L.Finn: "Analysis of the Behavior of Shallow Foundation by Non-linear Finite Element Method : (in Japanese)" Japanese Society of Soil Mechanics and Foundation Engineering, 35th. Symposium on the Analysis of the Behaviors of

K.Miura、K.Ueno、S.Toki 和 W.D.L.Finn：“用非线性有限元法分析浅层地基的行为：（日语）”日本土壤力学与基础工程学会，第 35 期。

三浦均也: "直接基礎の極限支持力推定法の提案" 土質工学研究発表会論文報告集. 25. (1990)

Hitoshi Miura：“直接地基极限承载力估算方法的建议”，土壤工程研究会议论文集，25。（1990）。

土岐祥介: "主応力軸回転場で繰返し荷重を受ける砂の変形挙動" 土質工学研究発表会論文報告集. 25. (1990)

Shosuke Toki：“在主应力轴旋转场中承受重复载荷的沙子的变形行为”土壤工程研究会议论文集 25。（1990）。

三浦,均也: "異方性地盤支持力の有限要素解析" 土木学会年次学術講演会講演集. 43. 252-253 (1988)

Miura，Hitunya：“各向异性土壤承载力的有限元分析”日本土木工程学会学术年会论文集 43. 252-253 (1988)。