Seepage caused tension failures and erosion undercutting of hillslopes

Chu-Agor, M. L.; Fox, Garey A.; Cancienne, Rachel M.; Wilson, George Grafton

doi:10.1016/j.jhydrol.2008.07.005

Cited by 99 publications

(89 citation statements)

References 19 publications

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“…Figure 4 shows the distribution of the critical hydraulic gradients that were predicted under different relative exposure degrees (∆ = 0.05, 0.1, 0.2) and different porosities (e = 0.43, 0.67, 1). For the vertical slope shown in Figure 4, the critical hydraulic gradient in the slope toe, where seepage erosion and seepage undercutting in the sand are most likely to happen, as demonstrated by Chu-Agor et al [1,34], is small. From the toe, up to the top, the critical hydraulic gradient gradually becomes larger.…”

Section: Qualitative Analysismentioning

confidence: 79%

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A Theoretical Model to Predict the Critical Hydraulic Gradient for Soil Particle Movement under Two-Dimensional Seepage Flow

Huang

Bai

et al. 2017

Water

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Abstract:The soil particle movement under seepage flow is one of the predominant mechanisms responsible for incidents and failures of dams and streambanks. However, little attention has been paid to the critical hydraulic gradient under two-dimensional (2-D) seepage flow. In this study, a theoretical model was established under 2-D seepage flow to predict the critical hydraulic gradients for soil particle movement. In this model, the sediment particle rolling theory was used, while taking into account the relative exposure degree of the soil grains and the seepage direction. The model was validated through qualitative analysis and comparison with previous data, and showed considerable superiority over Terzaghi's model. In addition, the effect of the soil internal instability, implying that the critical hydraulic gradient of unstable soil is lower than that of stable soil, was discussed. Various parameters of the model were also analyzed. The results showed that the seepage direction angle was positively related to the critical gradient, whereas the void and the mean diameter of the soil were negatively related to it. Finally, the model proposes a calculation method for the particle movement initiation probability, which is regarded as a key parameter in the sediment transport model.

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Section: Qualitative Analysismentioning

confidence: 79%

“…The soil-water pressure, seepage gradient forces, and the soil particle movement in relation to seepage erosion were the focus of previous studies [1,2]. Among these factors, seepage erosion is the predominant failure mechanism causing incidents in dams and streambanks [3,4], being responsible for approximately 50% of the failures [5,6].…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Model to Predict the Critical Hydraulic Gradient for Soil Particle Movement under Two-Dimensional Seepage Flow

Huang

Bai

et al. 2017

Water

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“…Therefore variables that aren't included in BSTEM, namely porosity and permeability, would likely be significant. Although seepage erosion has been directly quantified (Fox et al, 2007b), only early attempts have been made at developing regression models (Fox et al, 2007a(Fox et al, , 2006 and mechanistic models (Chu-Agor et al, 2008aFox and Felice, 2014) to predict erosion rates. Subaerial processes are controlled by freeze/thaw and wetting/drying cycles which loosens exposed soil (Couper and Maddock, 2001;Couper, 2003).…”

Section: Limitations Of This Study and Bstemmentioning

confidence: 99%

Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading

Lammers

Bledsoe

Langendoen

2016

Earth Surf Processes Landf

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UNCERTAINTY AND SENSITIVITY IN A BANK STABILITY MODEL: IMPLICATIONS FOR ESTIMATING PHOSPHORUS LOADINGEutrophication of aquatic ecosystems is one of the most pressing water quality concerns in the U.S. and around the world. Bank erosion has been largely overlooked as a source of nutrient loading, despite field studies demonstrating that this source can account for the majority of the total phosphorus budget of a watershed. Substantial effort has been made to develop mechanistic models to predict bank erosion and instability in stream systems; however, these models do not account for inherent natural variability in input values. Providing only single output values with no quantification of associated uncertainty can complicate management decisions focused on reducing bank erosion and nutrient loading to streams. To address this issue, uncertainty and sensitivity analyses were performed on the Bank Stability and Toe Erosion Model (BSTEM), a mechanistic model developed by the USDA-ARS that simulates both mass wasting (stability) and fluvial erosion of streambanks. Sensitivity analysis results indicate that variable influence on model output can vary depending on assumed input distributions.Generally, bank height, soil cohesion, and plant species were found to be most influential in determining stability of clay (cohesive) banks. In addition to these three inputs, groundwater elevation, stream stage, and bank angle were also identified as important in sand (non-cohesive) banks. Slope and bank height are the dominant variables in fluvial erosion modeling, while erodibility and critical shear stress are relatively unimportant. However, the threshold effect of critical shear stress (determining whether erosion occurs) was not explicitly accounted for, ii possibly explaining the relatively low sensitivity indices for this variable. Model output distributions of sediment and phosphorus loading rates corresponded well to ranges published in the literature, helping validate both model performance and selected ranges of input values. In addition, a probabilistic modeling approach was applied to data from a watershed-scale sediment and phosphorus loading study on the Missisquoi River, Vermont to quantify uncertainty associated with these published results. While our estimates indicated that bank erosion was likely a significant source of sediment and phosphorus to the watershed in question, the uncertainty associated with these predictions indicates that they should probably be considered order of magnitude estimates only.iii ACKNOWLEDGEMENTS

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“…This work includes the investigation of the relationships between ground movements and hydrological processes [1][2][3][4][5] (e.g. rainfall, ground water table variations), and the study of soil movements caused by the life processes of the vegetation.…”

Section: Introductionmentioning

confidence: 99%

A new borehole wire extensometer with high accuracy and stability for observation of local geodynamic processes

Mentes

2012

Review of Scientific Instruments

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Very stable and reliable instruments with high accuracy are required in field measurements for continuous monitoring local geodynamic processes, such as tectonic movements, ground motions in landslide prone areas, etc. A sensitive borehole wire extensometer with low energy consumption was developed in the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences to observe very small vertical movements (in the order of a few millimeters) of the upper layer of the soil due to hydrological, meteorological and biological processes. The newly developed instrument eliminates the disadvantages of the borehole wire extensometers which are presently used. Its sensitivity and stability are much higher than these parameters of the previous instruments. The instrument is able to measure distance variations without instrumental drift in a range of 0-4 mm with a resolution of better than 1 µm. Since the effect of the yearly temperature variations can be easily removed from 2 the extensometric data record, the compensation for the short-periodic (daily) thermal effects on the instrument was of high priority during the design of the instrument. This paper describes the construction and calibration of the extensometer. The extensometer was installed for monitoring vertical ground movements due to hydro-meteorological processes on the high loess wall of the Danube River at Dunaföldvár, Hungary. The efficiency of the temperature compensation of the instrument was investigated in detail on the basis of the measured data series.

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Seepage caused tension failures and erosion undercutting of hillslopes

Cited by 99 publications

References 19 publications

A Theoretical Model to Predict the Critical Hydraulic Gradient for Soil Particle Movement under Two-Dimensional Seepage Flow

A Theoretical Model to Predict the Critical Hydraulic Gradient for Soil Particle Movement under Two-Dimensional Seepage Flow

Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading

A new borehole wire extensometer with high accuracy and stability for observation of local geodynamic processes

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