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Overflow for the complete failure of the downstream shell of a rockfill dam




Alves, R. M., author
Toledo, M. Á., author
Morán, R., author
Colorado State University. Department of Engineering, publisher

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This paper presents the results of experimental research using physical models regarding the failure of the downstream shoulder of rockfill dams caused by overtopping. The aim of this investigation is to analyze how different parameters such as the rockfill permeability, the main geometric dimensions of the dam, or the impervious element type affect the flow that initiates failure and also the ultimate flow needed to break the downstream shell of the dam. The primary objective of this study is to develop predictive models for both discharge flows. For this purpose, tests with stepwise flow increments were performed by varying the rockfill size, the height and width of the dam, the downstream slope and the type of impervious element. The regression analysis was based on results from 61 experimental tests: 50 tests were used to calibrate the formulas and 11 were used for validation. The analysis shows that, for a given dam height, the failure and the initiation discharges depend essentially on the rockfill permeability and, to a lesser extent, on the slope of the downstream shell. The type of impervious element, central core, upstream face or the absence of this element, seems to have no significant effect.


Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.
Includes bibliographical references.

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rockfill dam
failure flow
dam protection


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