Mechanism of progressive failure in river dike during infiltration and overflow and its prediction

河堤渗溢过程渐进破坏机理及预测

• 批准号: 17560441
• 负责人: UZUOKA Ryosuke
• 金额: $ 2.46万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17560441/
• 关键词: geotechnical engineering; land protection; flood; disaster reduction; disaster prevention; river dike; infiltration; progressive failure; geotechnical engineering; land protection; flood; disaster reduction; disaster prevention; river dike; infiltration; progressive failure

The purpose of this study is to clarify the mechanism of progressive failure of river dike during the infiltration and overflow of river water. First, infiltration-shear tests during of unsaturated soil from actual river dike were performed in order to propose a constitutive model which can reproduce shear deformation during infiltration. As the results of the infiltration-shear tests, large shear strain was produced during infiltration under initial shear condition. An elasto-plastic constitutive model was newly proposed to reproduce the results of the infiltration-shear tests. The proposed constitutive model is based on super/sub loading surface Cam-Clay model and it has a modified evolution law which is a function of suction as an internal variable. The proposed model reproduced the increase in large shear strain during infiltration in the simulation of the infiltration-shear tests. Second, dynamic soil-water-air coupled analysis method at finite strain was developed. Static self-weight analyses, quasi-static consolidation analyses, dynamic consolidation analyses and quasi-static leaking flow analyses of unsaturated soil were performed in order to verify the developed numerical code. Preliminary analyses with elastic constitutive model showed that the proposed "aerial element" which has water retention characteristics of air and small stiffness could be used for direct modeling of river water. Although further investigations into convection term are needed, aerial element can be useful for the interaction analysis between overflow water and soil embankment. Third, progressive failure of river dike during infiltration of river water was simulated with the proposed constitutive model and numerical code. Although further investigations into implicit integration of stress are needed, the numerical results showed that seepage flow appeared at the landside toe of the dike and the slope became unstable at the waterside toe of the dike when the river level rose.

这项研究的目的是阐明河水渗透和溢出期间河流堤防的进行性失败的机理。首先，进行了来自实际河堤的不饱和土壤期间的浸润剪切试验，以提出一个组成型模型，该模型可以在浸润过程中重现剪切变形。作为浸润剪切测试的结果，在初始剪切条件下浸润期间产生了较大的剪切应变。新提出了一种弹性塑构模型，以重现浸润剪切测试的结果。所提出的本构模型基于超级/子加载表面凸轮 - 粘合模型，它具有修改的进化定律，该定律是吸力作为内部变量的函数。在浸润剪切测试的模拟中，提出的模型在浸润过程中重现了大剪切应变的增加。其次，开发了有限菌株时动态的土壤水 - 空气耦合分析方法。为了验证开发的数值代码，进行了静态的自重分析，准静态合并分析，动态巩固分析和准静态泄漏流量分析。使用弹性本构模型进行初步分析表明，提出的具有空气和较小刚度的水位特征的“空中元件”可用于直接建模河水。尽管需要进一步研究对流项，但天线元素可用于溢流水和土壤路堤之间的相互作用分析。第三，通过拟议的构造模型和数值代码模拟了河水渗透期间河堤的进行性失败。尽管需要进一步研究压力的隐式整合，但数值结果表明，堤防的地面脚趾出现了渗流，并且河流水平上升时堤防的水边脚趾变得不稳定。