Geomorphological processes due to intermittent sediment movements such as land slides and slope failures

间歇性沉积物运动（例如滑坡和斜坡崩塌）造成的地貌过程

• 批准号: 17360229
• 负责人: IZUMI Norihiro
• 金额: $ 3.48万
• 依托单位: Hokkaido University (2006-2007)Tohoku University (2005)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 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-17360229/
• 关键词: surface sheet flow; gully; channel bifurcation; seepage flow; slope failure; landslide; sediment hazard probability; snowmelt; 水路網; 分岐; 液状化; 不飽和土; 不飽和地盤; 動的解析; 有限要素法; 土砂災害; リスク; 水路群; 線形安定性理論; 地下水; パイピング; 斜面災害; 極値降雨

A mathematical model is proposed to describe the channelization on slopes composed of weakly cohesive fine sediment. The analysis is extended to include the case of slopes with arbitrary shapes. The spacing of incipient channels is found to be on the order of 1000 times the Froude critical depth of surface sheet flow. A mathematical model of channel bifurcation is also proposed. The analysis reveals that channel heads become unstable and channel bifurcation takes place when the discharge decreases. The results are found to be consistent with observations. The formation of channels due to seepage erosion is studied experimentally. It is found that governing parameters are discharge, slope and seepage layer thickness and that the spacing increases with those parameters.A liquefaction analysis for capillary zone above ground water level is developed based on porous media theory with three phases. Simplified governing equations are derived with the assumption that the relative acceleration of pore fluid with respect to soil skeleton is small. The proposed method can reproduce the tri-axial test results well when the degree of saturation is larger than about 70%. The numerical results show that liquefaction occurred in the capillary zone when the initial saturation degree is about 60% and over.Hydraulic gradient was analyzed by infiltration analysis with consideration of snowmelt. The probability and the road damage in the Tohoku region are shown in maps with 1 km resolutions. These maps show spatial-temporal risk distributions of sediment hazard due to some snowmelt conditions. We also focus on the influence of dam reservoirs to cause excessive sediment disasters due to anomalous weather conditions by global warming. Results of this study conform that the sediment hazard probability model performs well to predict macro scale sediment storage in dam reservoirs.

提出了一个数学模型来描述由弱凝聚力泥沙组成的斜率上的通道化。分析扩展到包括任意形状的斜率的情况。发现开始通道的间距在表面板流的临界深度的1000倍上。还提出了通道分叉的数学模型。分析表明，通道头变得不稳定，并在排放减少时进行通道分叉。发现结果与观察结果一致。通过实验研究了由于渗透侵蚀引起的通道的形成。发现管理参数是放电，坡度和渗漏层的厚度，并且间距随着这些参数而增加。基于具有三个阶段的多孔介质理论，开发了地下水位高于地下水位的毛细管区域的液化分析。简化的管理方程是通过假设孔相对于土壤骨架的相对加速度的假设。当饱和度大于70％时，提出的方法可以很好地再现三轴测试结果。数值结果表明，当初始饱和度约为60％及以上时，在毛细管区域发生液化。通过浸润分析分析了液压梯度，并考虑融雪。 Tohoku地区的概率和道路损坏显示在图1公里的地图中。这些地图显示，由于某些融雪的条件，沉积物危险的时空风险分布。我们还专注于大坝水库的影响，因为由于全球变暖，由于天气异常的天气条件，导致过度的沉积物灾难。这项研究的结果符合沉积物危险概率模型的表现，可以很好地预测大坝储层中的宏观秤沉积物。

项目成果

斜面上に形成される水路の分岐過程について

关于斜坡上形成的水道的分支过程

• 发表时间: 2007
• 期刊: 平成18年度土木学会東北支部技術研究発表会講演概要集
• 作者: H. Mizushima;N. Izumi and G. Parker;水嶋大樹
• 通讯作者: 水嶋大樹

ガリの発達とそれに伴う土砂生産過程

沟渠及相关沉积物生产过程的开发

• 发表时间: 2006
• 期刊: 水工学論文集 Vol.50
• 作者: H. Mizushima;N. Izumi and G. Parker;水嶋大樹;川越清樹;川越清樹;水嶋大樹
• 通讯作者: 水嶋大樹

任意形状を有する斜面上における水路形成の線形安定論

任意形状边坡河道形成的线性稳定性理论

• 发表时间: 2006
• 期刊: 土木学会論文集 No.810/II-74
• 作者: H. Mizushima;N. Izumi and G. Parker;水嶋大樹;川越清樹;川越清樹;水嶋大樹;泉 典洋
• 通讯作者: 泉 典洋

Fundamental study on water quality of reservoirs and slope failures in basins

水库水质与流域边坡破坏基础研究

• 发表时间: 2007
• 作者: Akimoto;T.;Kawagoe;S.;Kazama;S. and Sawamoto;M.
• 通讯作者: M.

Risk evaluation of sediment hazard due to snowmelt in Japan

日本融雪泥沙灾害风险评估

• 发表时间: 2008
• 期刊: Annual J. of Hydraulic Engineering Vol. 52
• 作者: Kawagoe;S.;Kazama;S. and Sawamoto;M.
• 通讯作者: M.