A numerical geotechnical model for computing soil slides at banks of water reservoirs
- PDF / 7,123,347 Bytes
- 23 Pages / 595.276 x 790.866 pts Page_size
- 88 Downloads / 149 Views
RIGINAL RESEARCH
Open Access
A numerical geotechnical model for computing soil slides at banks of water reservoirs Nils Reidar B. Olsen1* and Stefan Haun2
*Correspondence: [email protected] 1 Department of Civil and Environmental Engineering, The Norwegian University of Science and Technology, Trondheim, Norway Full list of author information is available at the end of the article
Abstract Soil slides can occur when the water level in a lake or a reservoir is lowered. This may take place in situations when a reservoir is flushed to remove sediments. The current study describes a three-dimensional numerical model used for the simulation of reservoir flushing that includes the slide movements. The geotechnical failure algorithms start with modelling the groundwater levels at the banks of the reservoir. A limit equilibrium approach is further used to find the location of the slides. The actual movement of the sediments is computed by assuming the soil to be a viscous liquid and by solving the Navier–Stokes equations. The resulting bed elevation changes from the slides are computed in adaptive grids that change as a function of water level, bed erosion and slide movements. The numerical model is tested on the Bodendorf reservoir in Austria, where field measurements are available of the bank elevations before and after a flushing operation. The results from the numerical simulations are compared with these observations. A parameter test shows that the results are very sensitive to the cohesion and less sensitive to the E and G modules of the soil. Keywords: Sediments, Bank failure, Numerical modelling, Navier–stokes equations, Limit equilibrium model, Finite volume method
Introduction Water is a valuable resource in most parts of the world. It is stored in reservoirs and used for several purposes, such as irrigation or hydropower. Many rivers carry large amounts of sediments, which can deposit in the impounded reservoir behind the dams and seriously reduce the water storage capacity. Mahmood [1] estimated that around 1% of the total water reservoir volume in the world is lost annually due to sedimentation. Several regions in the world show much higher sedimentation values. The most common method to mitigate the problem is to carry out a draw-down flushing by lowering the water levels [2]. This method has shown to be the most cost-effective alternative for many reservoirs. However, the success of reservoir flushing is depending on a variety of parameters [3]. The flushing also has some disadvantages. The environmental impact can be significant in case of an incorrect flushing strategy and/or the absence of sufficient monitoring procedures. Most of the water in the reservoir is lost after the flushing, © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creati
Data Loading...
