Proceedings of the
8th International Symposium on Geotechnical Safety and Risk (ISGSR)
14 – 16 December 2022, Newcastle, Australia
Editors: Jinsong Huang, D.V. Griffiths, Shui-Hua Jiang, Anna Giacomini, Richard Kelly
doi:10.3850/978-981-18-5182-7_16-005-cd
Uncertainty in the Critical Secant Gradient Function for Prediction of Backward Erosion Piping
1Risk Management Center, U.S. Army Corps of Engineers, 12596 W Bayaud Ave, Lakewood, CO, USA.
2Department of Civil and Environmental Engineering, Colorado School of Mines, 1500 Illinois Street, Golden, CO, USA.
ABSTRACT
Backward erosion piping is a type of internal erosion that occurs when small erosion channels progress through erodible foundation materials beneath an embankment in the direction opposite of flow. Recent research has proposed the concept of a critical secant gradient function (CSGF) as a means of quantifying the critical hydraulic conditions for erosion progression. In this study, uncertainty in the prediction of the CSGF was evaluated through a series of 24 laboratory measurement on different soils. An analytical solution for the CSGF was fitted to each experiment, and a model for predicting the analytical CSGF was developed through a non-linear multivariate analysis of the results. Results indicate that the uncertainty in the CSGF is relatively small as indicated by the narrow confidence intervals on the predicted CSGF values. Additionally, the model for predicting the CSGF was found to reliably bound the measured CSGF values with 95% confidence for 20 of the 24 experiments conducted. This suggests that the CSGF can be reliably predicted based on soil gradation characteristics for clean sands.
Keywords: internal erosion, backward erosion piping, levees, dams, prediction
