Fast DEM Modelling Approach for Internal Erosion of Barrier Dam Granular Materials Based on Acceleration Field

The barrier dams are loose accumulation bodies formed by collapse, landslide, debris flow or moraine, and most of them are composed of loosely and widely graded cohesionless soil. The barrier dams are susceptible to internal erosion during the rapid rising of upstream water level, and threaten the downstream residents' property and life safety. CFD-DEM coupling approach is often used to model the internal erosion of barrier dam, but it often costs lots of time due to the coupling counting and corresponding data processing. Based on the encountered forces of cohesionless soils of barrier dams during the process of seepage failure, the fluid force applied to the particles was analyzed and a simplified method to modeling the internal erosion process with the discrete element method was suggested. Utilizing this method, the encountered fluid force of a particle in the flow field was applied to the DEM module in the form of an acceleration field. Then, the amount of calculation required for the dual-module interactive iteration in the traditional CFD-DEM coupling method could be reduced, and it could effectively improve the calculation efficiency based on retaining the calculation effect of the CFD-DEM coupling method. Finally, pointing at the wide-graded non-cohesive dam soil materials, the simplified ideal gap-graded sized particle model was used to compare the CFD-DEM coupling calculation results to verify the rationality and effectiveness of the fast calculation method proposed in this paper. It showed that the relative error was within 3.4%, which proved the reliability of the simplified simulation method. When a simplified simulation method was adopted to simulate specific cases, the specific magnitude of the error might change. In terms of calculation speed, the running speed of the fast simulation method in this simulation was approximately 3.5 times than that of the CFD-DEM coupled simulation method, and when the number of particles increased, the calculation speed of the simplified simulation method increased significantly. Copyright ©2020 Advanced Engineering Sciences. All rights reserved.