Development and experimental validation of a multiscale DEM-FEM model for core overtopping in embankment dams

点击翻译按钮获取中文摘要

Core overtopping occurs when the water level rises over the impermeable core, into the filter of zoned**embankment dams. It can lead to internal erosion at the interface between core and filter, and eventually to dam**failure. Core overtopping can be avoided by maintaining a low water level in the upstream reservoir. However,**low reservoir levels can have economic consequences for dam owners. Experimental data on the progression of**contact erosion during core overtopping for complex dam geometries, transient flow and widely graded core**materials are scarce. As a consequence, it is important for dam owners to get a better understanding of the real**impact of core overtopping. The main objectives of this project are to gather experimental data on core**overtopping for realistic geometries, materials and flow conditions, and to develop a numerical model for this**phenomenon. In the first phase of the project, core overtopping will be replicated experimentally with a**laboratory model for different core and filter grain size distributions. The tested materials will be chosen so that**some combinations fail to respect the accepted design criteria for stability against erosion. Combinations**representative of Canadian embankment dams with a widely graded core will be tested. In the second phase of**the project, a numerical model will be programmed to replicate the experimental results. The continuum**models that are widely used in practice perform poorly when modelling phenomena that are dependent on**microscale behaviour, such as internal erosion. The numerical model will be based on a novel multiscale**approach. It will combine particle scale modelling with the discrete element method, where the displacement of**individual particles is modelled (software YADE), and large scale modelling with the finite element method,**where the soil is modelled as a continuum (software COMSOL). There are currently more than 10,000 dams in**Canada. A practical multiscale model and experimental data on erosion threshold and rate of erosion for**realistic geometries and materials will allow appropriate actions to be taken in case of core overtopping. It will**also help design new structures.