Embankment Failures and Slope Protection of Earth Dams during Flooding

洪水期间土坝的路堤溃决与护坡

• 批准号: 08650584
• 负责人: NARITA Kunitomo
• 金额: $ 0.83万
• 依托单位: Aichi Institute of Technology (A.I.T.)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650584/
• 关键词: Fill Dam; Centrifuge Model Test; Pore Water Pressure; Seepage Failure; Overflow Failure; Slope Stabilization; FEM Analysis

Centrifuge model tests were carried out in order to investigate the mechanism of seepage failures of earth dams caused by a rapid increase of reservoir water during flooding, to know which factor should be the main trigger of fracture and when and how it works in the process of overall failure of the embankment. Feasibility of realizing seepage failures in laboratory model tests is another important subject to be discussed for future studies on hydraulic fracturing in earth and rockfill dams. Tests were conducted on several model earth dams made under different compaction conditions to examine their influence on the development of pore-water pressure in the fill.Two distinct patterns were noticed in embankment failures caused by a rapid increase of reservoir water during flooding. One is in case of dry and poorly compacted fill where internal erosion (piping) due to seepage water flow through the dam body is predominant, though over-flow water initially causes a little damage to the downstream surface by gully erosion and contributes to a trigger of piping. The other is in case of fill in wet and/or highly compacted state before flooding, in which surface gully erosion due to over-flow of water extends in a constant rate to the upstream side with a little internal erosion. Measurement of pore-water pressure and FEM analysis on the model tests somewhat revealed the mechanism of these embankment failures, though further studies are required to give more precise and quantitative discussions. Concerning the slope protection work against flooding, a few model tests were carried out to investigate by what material and where and how it should be constructed to get more effective protection. Much discussion is still needed on this subject to apply it for actual design and construction of embankments.

为探讨洪水过程中库水快速增加引起土坝渗流破坏的机理，了解哪些因素是导致土坝破裂的主要触发因素以及在土坝渗流过程中何时、如何发生作用，进行了离心模型试验。路堤整体破坏。在实验室模型试验中实现渗流破坏的可行性是未来土石坝水力压裂研究的另一个重要课题。对不同压实条件下建造的几个模型土坝进行了试验，以检验它们对填土中孔隙水压力发展的影响。在洪水期间水库水快速增加引起的路堤破坏中发现了两种不同的模式。一种是在干燥且压实不良的填土情况下，由于渗流水流经坝体而导致的内部侵蚀（管道）占主导地位，尽管溢流水最初会因沟渠侵蚀对下游表面造成轻微损害，并有助于触发的管道。另一种是淹没前填土处于潮湿和/或高度压实状态的情况，其中由于水溢出而导致的表面沟壑侵蚀以恒定的速度向上游侧延伸，内部侵蚀很少。模型试验中孔隙水压力的测量和有限元分析在一定程度上揭示了这些路堤破坏的机制，但需要进一步的研究来提供更精确和定量的讨论。针对防洪边坡防护工程，进行了一些模型试验，探讨采用什么材料、在哪里、如何施工才能得到更有效的防护。为了将其应用于路堤的实际设计和施工，仍然需要对此主题进行大量讨论。