Integrating Field Monitoring and Numerical Modeling to Evaluate Performance of a Levee under Climatic and Tidal Variations
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 145, Issue 10
Abstract
Several short-duration and extreme hydraulic loadings impose time-dependent variably saturated seepage conditions on earthen slopes and embankments. Difficulty assigning appropriate input parameters and lack of full-scale validation are among the main factors introducing uncertainty and lack of confidence when performing numerical transient seepage analysis. This case study demonstrates how to effectively use field-monitoring data to improve the numerical analysis of a levee under climatic and tidal variations. The case study includes a silty sand setback levee located near Seattle. An array of tensiometers and soil moisture sensors installed within the levee’s embankment and foundation, along with a nearly real-time data acquisition system, were used to collect and process the in situ data for a period of about 15 months. Climatic and weather data, including precipitation, temperature, humidity, and wind speed, were collected from a weather station at the site, and tidal water fluctuations were monitored using a water level sensor. The field-measured matric suction and water content were used along with a suction stress–based representation of effective stress to compute suction stress and effective stress profiles versus time. A finite-element model of transient seepage under saturated-unsaturated conditions was developed. The numerical model was calibrated and then validated using the measured pore-water pressures and the piezometric surface. The application of the numerical model was illustrated by modeling the seepage and stability of the levee during a 100-year flood event. The results highlight the need to consider climatic variables and soil–atmosphere interaction when performing transient seepage analysis.
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Acknowledgments
The authors acknowledge the Engineer Research and Development Center (ERDC) and Civil Works program for sponsoring this research. The authors thank Dr. Maureen Corcoran, Chris Price, and Joseph Bonelli for their continuous support of this study effort. The authors thank Sannith Kumar Thota for his assistance in revising the manuscript and preparing the final figures.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 145 • Issue 10 • October 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Nov 1, 2018
Accepted: May 1, 2019
Published online: Jul 22, 2019
Published in print: Oct 1, 2019
Discussion open until: Dec 22, 2019
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