The statistics of embankment dam failures and accidents
01 Oct 2000-Canadian Geotechnical Journal (NRC Research Press Ottawa, Canada)-Vol. 37, Iss: 5, pp 1000-1024
TL;DR: In this paper, the results of a statistical analysis of failures and accidents of embankment dams, specifically concentrating on those incidents involving piping and slope instability, are described. The results of the analysis are presented in Table 1.
Abstract: The paper describes the results of a statistical analysis of failures and accidents of embankment dams, specifically concentrating on those incidents involving piping and slope instability. The com...
Citations
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TL;DR: In this paper, the erosion characteristics of soil in cracks in embankment dams are described by the erosion rate index, which measures the rate of erosion, and the critical shear stress, which represents the minimum shear stresses when erosion starts.
Abstract: The slot erosion test and the hole erosion test have been developed to study the erosion characteristics of soil in cracks in embankment dams. The erosion characteristics are described by the erosion rate index, which measures the rate of erosion, and the critical shear stress, which represents the minimum shear stress when erosion starts. Values of the erosion rate index span from 0 to 6, indicating that soils can differ in their rates of erosion by up to 10 6 times. The rate of erosion is shown to be dependent on the soil fines and clay sized content, plasticity, and dispersivity; compaction water content, density and degree of saturation; and clay mineralogy, and possibly the presence of cementing materials such as iron oxides. Coarse-grained, noncohesive soils, in general, erode more rapidly and have lower critical shear stresses than fine-grained soils. Knowledge of the erosion characteristics of the soil in the core of an embankment dam aids in the assessment of the likelihood of dam failure due to piping erosion.
409 citations
TL;DR: A comprehensive review of published literature on soil piping phenomena can be found in this article, where the authors highlight the limitations of the occurrence of piping and the role that design and construction may play in a large percentage of piping failures.
Abstract: This paper presents a comprehensive review of published literature on soil piping phenomena. The first tools to design earth dams to resist piping were developed during 1910–1935. Filter criteria for dispersive soils was refined in the 1970’s. Piping phenomena are generally defined as: (1) heave, (2) internal erosion, (3) backwards erosion, although other modes are possible. Recent work on piping highlights the limitations of the occurrence of piping and the role that design and construction may play in a large percentage of piping failures. Standardized laboratory procedures are available to assess piping potential in cohesive materials, but no such methods exist for non-cohesive soils. However, methods are available for evaluation of self-filtration potential. Recent advances in computer technology have facilitated the evaluation of seepage and deformation in embankments but computational methods for evaluation of piping potential are currently limited.
299 citations
Cites background from "The statistics of embankment dam fa..."
...They reported 35% of piping failures through the embankment occurred more than 5 years after first filling and 59% occurred during the first 5 years (Foster et al. 2000a, p. 1017)....
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...This work, along with the statistical data of Foster et al. (2000a) is shedding some light on the causes of piping and causing engineers to reassess the failure mechanisms and genetic characteristics of piping (McCook 2004)....
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...Other recent work includes the collection of empirical data concerning dam failures by Foster et al. (2000b) and assessing the specific failure modes related to piping....
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TL;DR: In this paper, a method for the estimation of the time for progression of internal erosion and piping, and development of a breach leading to failure in embankment dams and their foundations is presented.
Abstract: A method is presented for the approximate estimation of the time for progression of internal erosion and piping, and development of a breach leading to failure in embankment dams and their foundations. The method accounts for the nature of the soils in the dam core, the foundation, and the materials in the downstream zone of the dam. Guidance is also provided on the detectability of internal erosion and piping, taking account of the mechanism of initiation, continuation, and progression to form a breach, for internal erosion and piping in the embankment, the foundation and from the embankment to foundation. It is shown that in many dams which have poor internal erosion and seepage control and are constructed mainly of earthfill, the time for potential development of piping is short, and for these dams continuous monitoring of seepage or surveillance would be needed to detect the piping in time to give warning of possible failure, and to give time to attempt intervention to prevent the failure.
288 citations
TL;DR: In this article, a parametric study was conducted to examine the influence of three critical parameters on clay and sand erosion mechanisms, and it was concluded that the erosion of the structure's clay fraction was due to suffusion.
Abstract: Within hydraulic earth structures (dikes, levees, or dams), internal seepage flows can generate the entrainment of the soil grains. Grain transportation affects both particle size distributions and porosity, and changes the mechanical and hydraulic characteristics of the earth's structure. The occurrence of failures in new earth structures due to internal erosion demonstrates the urgency of improving our knowledge of these phenomena of erosion. With this intention, a new experimental device has been developed that can apply hydraulic stresses to reconstituted consolidated cohesive soils without cracks in order to characterize the erosion evolution processes that might be present. A parametric study was conducted to examine the influence of three critical parameters on clay and sand erosion mechanisms. When the hydraulic gradient was low, it was concluded that the erosion of the structure's clay fraction was due to suffusion. When the hydraulic gradient increased, it was concluded that the sand fraction erosion initiation was due to backward erosion. The extent of the erosion was dependent on the clay content. The study underlines the complexity of confinement stress effects on both erosion phenomena.
228 citations
Cites background from "The statistics of embankment dam fa..."
...Among 11,192 surveyed dams Foster et al. 2000 , 136 show dysfunctions, which are divided up as 5.5% related to sliding, 48% related to overtopping, and 46% related to internal erosion....
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TL;DR: In this article, the authors highlight the mechanisms and importance of subsurface flow processes in erosion associated with hillslopes and stream banks, and they believe that multidisciplinary efforts between soil scientists, geotechnical engineers, hydraulic engineers, and hydrologists are necessary to fully understand and integrate subsural surface flow and soil erosion processes in simulation tools.
Abstract: Sediment is one of the most common causes of stream impairment. Great progress has been made in understanding the processes of soil erosion due to surface runoff and incorporating these in prediction technologies. In many landscapes, however, the dominant source of sediment is derived from mass wasting of hillslopes and stream banks, potentially driven by subsurface flow. We highlight the mechanisms and importance of subsurface flow processes in erosion associated with hillslopes and stream banks. Subsurface flow affects erosion directly by seepage and pipe flow processes and indirectly by the relationship of soil properties with soil water pressure. Seepage contributes to erosion through interrelated mechanisms: hydraulic gradient forces that reduce the resistance of the particle to dislodging from the soil matrix and particle mobilization when soil particles become entrained in exfiltrating water. Preferential flow through soil pipes results in internal erosion of the pipe, which may produce gullies by tunnel collapse. The eroded material can clog soil pipes, causing pore water pressure buildup inside the pipes that can result in landslides, debris flows, embankment failures, or reestablishment of ephemeral gullies. Research in the past decades has advanced our understanding of these processes, leading to mathematical relationships that can be incorporated into mechanistic, process-based models. Further research advances are necessary, however, especially on the complexity of the interactive effects of surface flow, seepage, pipe flow, and vegetation on soil erosion properties. More information is needed on the extent that subsurface flow contributes to hillslope and stream bank erosion. We believe that multidisciplinary efforts between soil scientists, geotechnical engineers, hydraulic engineers, and hydrologists are necessary to fully understand and integrate subsurface flow and soil erosion processes in simulation tools.
193 citations
References
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TL;DR: In this paper, a method is presented for assessing the particle size distribution of the filters in a dam compared to the soil the filter is protecting, to determine whether the filters are sufficiently fine to give no, excessive, or continuing erosion.
Abstract: A method is presented for assessing the particle size distribution of the filters in a dam compared to the soil the filter is protecting, to determine whether the filters are sufficiently fine to give no, excessive, or continuing erosion. The method is based on the analysis of the results of laboratory tests and the characteristics of dams that have experienced piping incidents. The method can be used to determine whether filters that are coarser than required by modern filter design criteria will eventually seal or experience continuing erosion leading to possible failure of the dam in the event piping initiates.
142 citations
TL;DR: A method for estimating the relative likelihood of failure of embankment dams by piping, based on an analysis of historic failures and accidents, was proposed by the University of New South Wales (UNSW) as discussed by the authors.
Abstract: A method for estimating the relative likelihood of failure of embankment dams by piping, the University of New South Wales (UNSW) method, is based on an analysis of historic failures and accidents ...
139 citations
Book•
01 Jul 1992
TL;DR: In this paper, the authors present a "state of practice", particularly highlighting common problems, errors and omissions in embankment dams, weathering processes, geotechnical investigations, and foundation grouting.
Abstract: The aim of this book is to present a "state of practice", particularly highlighting common problems, errors and omissions. Topics addressed include embankment dams, weathering processes, geotechnical investigations, and foundation grouting.
95 citations
TL;DR: The ancient civilizations the Roman Empire the Moslem world medieval eastern Asia medieval and postmedieval Europe evolution of modern dam technology chronology as mentioned in this paper, see Section 2.2.1.
Abstract: The ancient civilizations the Roman Empire the Moslem world medieval eastern Asia medieval and postmedieval Europe evolution of modern dam technology chronology.
88 citations
TL;DR: In this paper, a history of parallel development of earth core and concrete-face rockfill dams and the impact of compacted rockfill on the concrete face rockfill dam is discussed.
Abstract: Karl Terzaghi, a major contributor to progress in embankment dams, made significant contributions to the understanding of properties of rockfill and to the improvement of design of the concrete-face rockfill dam His contributions are noted and followed by a history of parallel development of earth core and concrete-face rockfill dams and the impact of compacted rockfill on the concrete face rockfill dam Emphasis in this paper is directed towards the concrete face type of rockfill dam, since the earth core type is already well-covered in the literature Recent progress in the design and construction of the concrete-face rockfill dam is outlined and documented Design trends and performance data are presented
68 citations