Study on Time-Dependent Behavior of Saturated Soils due to Loss of Structure based on Elasto-Plastic Mechanics

基于弹塑性力学的结构损失引起的饱和土时变行为研究

• 批准号: 12450190
• 负责人: ASAOKA Akira
• 金额: $ 8.77万
• 依托单位: NAGOYA 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 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450190/
• 关键词: Natural deposit clay; Secondary consolidation; Soil structure; Overconsolidation; Anisotropy; Sanmpling; Elasto-plasticity; Soil-water coupled analysis; 弾塑性力学; 粘土; 圧密; せん断; 弾塑性構成式; 時間依存挙動

Natural deposit clay in highly structured, overconsolidated and anisotropy states is said to exhibit decrease of undrained shear strength due to sampling disturbance and time-dependent behavior such as "secondary consolidation/delayed compression" and "isotache" more remarkably than its remolded clay. In the present study, such behavior of the soil is investigated based on elasto-plastic mechanics and soil-water coupled analysis with experimental works. The main concluding remarks are as follows : 1) Colloidal clay reconstituted through self-weight consolidation in laboratory, which has significantly high water content, is highly structured, I.e. bulky compared with destructured/fully remolded clay. The clay approaches to destructured state as plastic deformations proceeds even in one-dimensional stress application. 2) In the numerical works, an elasto-plastic constitutive model for natural clays is newly proposed considering three concepts of soil structure, overconsolidation and anisotropy and their evolution rules. Furthermore, partially in the analysis, the v-lnp ' relationship is replaced by Inv-lnp ' to describe the self-weight consolidation process I.e. the large amount of compression behavior which occurs more remarkable in natural deposit soil, while v and p 'show specific volume and mean effective stress respectively. 3) Secondary consolidation of natural soil observed in oedometer tests if investigated from the numerical point of view. The behavior is attributed to not only high degree of structure of natural clay in itself but also increase/generation of overconsolidation accompanied with "sampling operation". Furthermore, in case that direction of sampling is different from that of axes of anisotropy, the secondary consolidation happens more easily.

据说，由于采样干扰和时间依赖性行为，例如“二级巩固/延迟压缩”和“ iSotache”，在高度结构化，超固结和各向异性状态下的天然沉积粘土表现出不排水的剪切强度的降低。在本研究中，基于弹性塑料力学和土壤 - 水偶联分析与实验著作一起研究了土壤的这种行为。总结的主要评论如下：1）胶体粘土通过实验室中的自重巩固重建，该实验室的水含量显着高，是高度结构化的，即与破坏性/完全重新恢复的粘土相比，笨重。随着塑性变形即使在一维应力应用中也会进行，粘土的方法可以破坏状态。 2）在数值工作中，考虑了三个土壤结构，过度溶解和各向异性及其进化规则的三种概念，新提出了用于自然粘土的弹性塑构模型。此外，部分在分析中，V-LNP的关系被Inv-LNP替换为描述自重的合并过程，即在天然沉积土壤中发生的大量压缩行为更为显着，而V和P'分别显示特定的体积和平均有效应力。 3）如果从数值的角度研究了氧化表测试中观察到的自然土壤的次要合并。这种行为不仅归因于自然粘土本身的高度结构，而且还增加了与“采样操作”相伴的过度固化。此外，如果采样方向与各向异性轴的方向不同，则次级巩固更容易发生。

项目成果

A.Asaoka et.al.: "The decay of structure and the loss of overconsolidation"Proc. of The Fifteenth International Conference on Soil Mechanics and Geotechnical Engineering. 1. 19-22 (2001)

A.Asaoka 等人：“结构的衰变和超固结的损失”Proc。

Asaoka, A: "An Elasto-Plastic Description of the Difference between Sand and Clay"Proc of The 10th International Conference IACMAG. Vol.1. 263-270 (2001)

Asaoka, A：“沙子和粘土之间差异的弹塑性描述”第十届国际会议 IACMAG 的会议记录。

A.Asaoka: "Decay of structure and loss of overconsolidation"Proc. of The International Workshop on Deformation Of Earth Materials. 1. 109-118 (2001)

A.Asaoka：“结构的衰变和超固结的损失”Proc。

Asaoka, A.: "An Elasto-Plastic Description of the Difference between Sand and Clay"Proc. of The 10th International Conference IACMAG. 1. 263-270 (2001)

Asaoka, A.：“沙子和粘土之间差异的弹塑性描述”Proc。

Noda T: "Sensitivity ratio' and 'sampling disturbance' of natural soils in terms of degradation of soil structure"Coastal Geotechnical Engineering in Practice, Proc. Of The International Symposium IS-YOKOHAMA. Vol.1. 113-118 (2000)

Noda T：“天然土壤在土壤结构退化方面的敏感性比”和“采样扰动”，沿海岩土工程实践，Proc。