SGER: Understanding the mechanics of particle motion in levee-breach closure

堤防决口截流中质点运动机理的认识M.哈尼夫·乔杜里和艾哈迈德·卡西姆摘要卡特里娜飓风过后，新奥尔良市的几处堤坝被冲垮，大部分地区被淹没。试图关闭最关键的堤坝决口17街运河使用沙袋高达10,000磅和直升机运输是不成功的。由于有关决口封堵的可用信息有限，必须采用试错法，这导致封堵需要很长时间，并导致大面积洪水泛滥。 与此相比，为了导流建坝，已经进行了大量的实验室和现场调查，以研究围堰的关闭，并且这些研究中开发的几个概念可以扩展到堤坝关闭。 围堰研究是基于对倾倒材料运动的视觉观察，可以利用目前可用的先进数字颗粒跟踪测速技术（DPTV）进行改进，该技术允许可靠和准确地测量颗粒运动，这对于理解该过程的力学至关重要。例如，最近在我们的水力实验室利用内部资金对第17街运河决口的1：50比例的物理模型进行了初步测试，结果表明，沙袋位置的轻微变化会极大地影响决口的移动。在拟议的研究中，我们将探讨DPTV技术的适用性，了解颗粒运动的力学，延长围堰关闭方法的堤坝决口关闭，并制定新的方法来确定最佳的颗粒尺寸。预期的结果包括DPTV的算法的发展，以可视化倾倒的材料的运动和理解的颗粒运动的力学，以确定堤坝关闭的材料的最小尺寸。本研究结果为未来堤防溃口之系统性最佳截流程序之研究奠定基础。虽然新奥尔良最近堤坝倒塌的原因正在一些机构进行调查，但据我们所知，没有调查正在进行中，因为这是一项同样重要的任务，即关闭决口。 本研究的目的是启动初步研究，以便将决口封堵和洪水淹没的时间和成本降至最低。拟议的研究是探索性的，因为它代表了“未经检验的想法的初步工作”。不同的DPTV技术可在文献中获得，并已用于其他几种应用中。这些技术还没有被用来可视化倾倒材料的运动和突破关闭的演变。需要这些初步数据来准备一个全面的堤坝关闭研究的完整建议。 这项研究的更广泛影响包括一名研究生和两名本科生的参与，特别是来自代表性不足的群体。 此外，随着这些研究的进展，将与比利时天主教大学和瑞士联邦技术研究所交流信息，在这两个研究所，对堤坝决口进行了广泛的调查，并发表了同行审查的期刊，以便普遍传播调查结果。

Understanding the mechanics of particle motion in levee breach closureM. Hanif Chaudhry and Ahmed KassemABSTRACTSeveral levees were breached following hurricane Katrina, inundating most of the city of New Orleans. Attempts to close the most critical levee breach on the 17th Street Canal using sandbags as large as 10,000 pounds and transported by helicopters were unsuccessful. Due to limited available information on breach closure, trial-and-error procedures have to be utilized which result in taking long times for closure and extensive flooding. As compared to this, considerable laboratory and field investigations for the closures of cofferdam have been conducted for river diversion to build dams and several concepts developed in these studies could be extended to levee closure. The cofferdam studies were based on visual observations of the motion of the dumped material which can be improved utilizing presently available advanced digital particle tracking velocimetry (DPTV) techniques that allow reliable and accurate measurements of the particle movements which are critical for the understanding the mechanics of the process. For example, preliminary tests on a 1:50 scale physical model of the 17th Street Canal breach built recently in our hydraulic laboratory utilizing internal funds show that a slight change in the positioning of a sandbag to close the breach dramatically affects its movement. In the proposed research, we will explore the applicability of DPTV techniques for the understanding of the mechanics of particle motion, to extend the cofferdam closure methods for the closure of levee breach and to develop new methodologies for determining the optimum particle size. The expected results include the development of an algorithm for the DPTV to visualize the motion of the dumped material and understanding the mechanics of particle motion for determining the minimum size of the material for levee closure. The findings of this research represent a base for future research on developing systematic optimum procedures for the closure of levee breaches. Although the causes of the recent levee failure in New Orleans are being investigated at a number of institutions, to the best of our knowledge, no investigations are in progress for an equally important task for the breach closure. The objective of this study is to initiate preliminary research so that the time and costs of breach closure and flooding are minimized. The proposed research is exploratory in nature as it represents "preliminary work on untested ideas". Different DPTV techniques are available in the literature and have been used in several other applications. These techniques have not been used to visualize the motion of the dumped material and the evolution of breach closure. These preliminary data are needed to prepare a full proposal for a comprehensive study for levee closure. The broader impacts of the study include the participation of one graduate and two undergraduate students, especially from the under-represented groups. In addition, as these studies progress, information will be exchanged with the Catholic University, Belgium and Swiss Federal Institute of Technology, Switzerland, where extensive investigations have been conducted on dam and dyke breaches as well as peer-reviewed journal publications for the universal dissemination of results.