Effect of Pressure Gradient on Critical Shear Stress of Cohesive Soils
Publication: Journal of Hydraulic Engineering
Volume 146, Issue 6
Abstract
Part of the difficulty in simulating or understanding the erosion of cohesive soils is the near impossibility of replicating field conditions, including the constantly varying pore water pressure and resulting seepage pressures in response to changing overlying flow depth and groundwater conditions. Unlike granular soils, for which pore pressures respond to imposed conditions in a relatively short time, pore pressures in cohesive soils tend to take considerable time to reach steady state under new imposed conditions. Consequently, pore pressure gradients can exist within the soil matrix. Herein, we evaluate the influence of pore pressure gradients on critical shear stress for entrainment of cohesive soils. The Erosionometer, a test device previously introduced for fast and accurate determination of the critical shear stress of cohesive soils based on physical shearing and uplifting of the soil surface, is modified to test for the critical shear stress while a hydraulic pressure gradient is applied to the sample surface. Tests on multiple cohesive soils demonstrate that the critical shear stress increases linearly with increasing drainage gradient (downward seepage pressure).
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request, including data not listed explicitly in this article such as the Erosionometer force versus probe movement raw data plotted in Figs. 9–11 and 13.
Acknowledgments
The authors offer many thanks to the City of Ottawa, and in particular Darlene Conway, for supporting the project, Mr. Mark Lapointe for his valuable assistance in fabrication of lab and field setups, and Guillaume Dreysse, Nicholas Zorn, Benjamin Lambert, Alain Kayitaba, and Andre Smith for assisting in field and laboratory work.
References
Al-Madhhachi, A., G. Fox, G. Hanson, A. Tyagi, and R. Bulut. 2014a. “Mechanistic detachment rate model to predict soil erodibility due to fluvial and seepage forces.” J. Hydraul. Eng. 140 (5): 04014010. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000836.
Al-Madhhachi, A. T., G. Fox, and G. J. Hanson. 2014b. “Quantifying the erodibility of streambanks and hillslopes due to surface and subsurface forces.” Trans. ASABE 57 (4): 1057–1069. https://doi.org/10.13031/trans.57.10416.
Briaud, J. L., F. C. K. Ting, H. C. Chen, R. Gudavalli, S. Perugu, and G. Wei. 1999. “Sricos: Prediction of scour rate in cohesive soils at bridge piers.” J. Geotech. Geoenviron. Eng. 125 (4): 237–246. https://doi.org/10.1061/(ASCE)1090-0241(1999)125:4(237).
Chu-Agor, M. L., G. A. Fox, R. M. Cancienne, and G. V. Wilson. 2008. “Seepage caused tension failures and erosion undercutting of hillslopes.” J. Hydrol. 359 (3–4): 247–259. https://doi.org/10.1016/j.jhydrol.2008.07.005.
Crowley, R., C. Robeck, and R. Thieke. 2014. “Computational modeling of bed material shear stresses in piston-type erosion rate testing devices.” J. Hydraul. Eng. 140 (1): 24–34. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000797.
Fox, G. A., and G. V. Wilson. 2010. “The role of subsurface flow in hillslope and streambank erosion: A review.” Soil Sci. Soc. Am. J. 74 (3): 717–733. https://doi.org/10.2136/sssaj2009.0319.
Fox, G. A., G. V. Wilson, A. Simon, E. J. Langendoen, O. Akay, and J. W. Fuchs. 2007. “Measuring streambank erosion due to ground water seepage: Correlation to bank pore water pressure, precipitation and stream stage.” Earth Surf. Processes Landforms 32 (10): 1558–1573. https://doi.org/10.1002/esp.1490.
Hanson, G. J. 1991. “Development of a jet index to characterize erosion resistance of soils in earthen spillways.” Trans. ASAE 34 (5): 2015–2020. https://doi.org/10.13031/2013.31831.
Hanson, G. J., and K. R. Cook. 2004. “Apparatus, test procedures, and analytical methods to measure soil erodibility in situ.” Am. Soc. Agric. Eng. 20 (4): 455–462.
Hollick, M. 1976. “Towards a routine test for the assessment of critical tractive forces of cohesive soils.” Trans. ASAE 19 (6): 1076–1081.
Julian, J. P., and R. Torres. 2006. “Hydraulic erosion of cohesive riverbanks.” Geomorphology 76 (1–2): 193–206.
Kamphuis, J. W., and K. R. Hall. 1983. “Cohesive material erosion by unidirectional current.” J. Hydraul. Eng. 109 (1): 49–61. https://doi.org/10.1061/(ASCE)0733-9429(1983)109:1(49).
Lambe, T. W., and R. V. Whitman. 1969. Soil mechanics, 553. New York: Wiley.
Mazurek, K. A., N. Rajaratnam, and D. Sego. 2001. “Scour of cohesive soil by submerged circular turbulent impinging jets.” J. Hydraul. Eng. 127 (7): 598–606. https://doi.org/10.1061/(ASCE)0733-9429(2001)127:7(598-606.
McNeil, J., C. Taylor, and W. Lick. 1996. “Measurements of erosion of undisturbed bottom sediments with depth.” J. Hydraul. Eng. 122 (6): 316–324. https://doi.org/10.1061/(ASCE)0733-9429(1996)122:6(316).
Midgley, T. L., G. A. Fox, G. V. Wilson, D. M. Heeren, E. J. Langendoen, and A. Simon. 2013. “Seepage-induced streambank erosion and instability: In situ constant-head experiments.” J. Hydrol. Eng. 18 (10): 1200–1210. https://doi.org/10.1061/(ASCE)HE.1943-5584.0000685.
Moore, W. L., and F. D. Masch. 1962. “Experiments on the scour resistance of cohesive sediments.” J. Geophys. Res. 67 (4): 1437–1449. https://doi.org/10.1029/JZ067i004p01437.
Nouwakpo, S. K., and C. Huang. 2012. “The role of subsurface hydrology in soil erosion and channel network development on a laboratory hillslope.” Soil Sci. Soc. Am. J. 76 (4): 1197–1211. https://doi.org/10.2136/sssaj2012.0013.
Nouwakpo, S. K., C.-H. Huang, L. Bowling, and P. Owens. 2010. “Impact of vertical hydraulic gradient on rill erodibility and critical shear stress.” Soil Sci. Soc. Am. J. 74 (6): 1914. https://doi.org/10.2136/sssaj2009.0096.
Salem, H., and C. D. Rennie. 2017. “Practical determination of critical shear in cohesive soils.” J. Hydraul. Eng. 143 (10): 04017045. https://doi.org/10.1061/(ASCE)HY.1943-7900.0001363.
San, L., and N. Khalili. 2009. “An improved rotating cylinder test design for laboratory measurement of erosion in clayey soils.” Geotech. Test. J. 32 (3): 232–238. https://doi.org/10.1520/GTJ101448.
Simon, A., and A. J. Collison. 2001. “Pore-water pressure effects on the detachment of cohesive streambeds: seepage forces and matric suction.” Earth Surf. Processes Landforms 26 (13): 1421–1442. https://doi.org/10.1002/esp.287.
Terzaghi, K. V. 1936. “The shearing resistance of saturated soils and the angle between the planes of shear.” In Vol. I of Proc., 1st Int. Conf. on Soil Mechanics and Foundation Engineering, 54–56. London: International Society for Soil Mechanics and Geotechnical Engineering, Univ. of London.
Wilson, B. N. 1993a. “Development of a fundamental based detachment model.” Trans. ASAE 36 (4): 1105–1114. https://doi.org/10.13031/2013.28441.
Wilson, B. N. 1993b. “Evaluation of a fundamental based detachment model.” Trans. ASAE 36 (4): 1115–1122.
Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 146 • Issue 6 • June 2020
Copyright
©2020 American Society of Civil Engineers.
History
Received: Jan 5, 2019
Accepted: Nov 20, 2019
Published online: Apr 8, 2020
Published in print: Jun 1, 2020
Discussion open until: Sep 8, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.