Long-term Monitoring at a Levee of Red River in Vietnam
A. Weller, R. Lewis, C. Tran, M. Möller and B. Scholz
Event name: Near Surface Geoscience 2013 - 19th EAGE European Meeting of Environmental and Engineering Geophysics
Session: Best of SAGEEP
Publication date: 09 September 2013
Info: Extended abstract, PDF ( 1.23Mb )
Price: € 20
A long term monitoring has been performed at a levee of Red River in Vietnam. The monitoring system consists of a permanent electrode array for resistivity imaging and geotechnical tools including tensiometers, frequency domain reflectometry sensors and an observation well. The components were installed after a detailed inspection of the levee and foundation by drilling, sampling, and a geoelectrical survey. The levee monitoring system provided time series of the sensor data that were related to the variation of pore water pressure and water distribution. The data clearly indicate the influence of variations of the water level in the Red River during the monsoon season and also the drying process of the levee thereafter. Furthermore, it was possible to observe the upward and downward movement of the seepage line within the levee. A two-dimensional transient finite element modelling of the seepage and groundwater flow was performed using the database of a single flood season. The resulting hydraulic model was used for a stability analysis. It could be shown that the stability calculations taking into account the transient development of the seepage line enables a more favourable safety factor in the stability analysis in comparison with the conventional steady state approach.