Abstract: As a prominent engineering problem in the dam bank of Yellow River, the loss of root stones directly affects the foundation stability and overall safety of dam foundation. In this paper, a numerical model of root stone scouring and collapse is built via Flow-3D and verified by physical model test example. Numerical calculation results are in agreement with physical model test results, indicating that the numerical model is available. Furthermore, the process of bed scouring is simulated using the numerical model, and results reveal that scouring pit at the front head of the dam appears the earliest and the pit is the deepest. With the continuous flow of water, the scouring pit develops towards the upstream cross corner area and the downstream cross corner area where the pit depths are similar. Sediment deposits at the dam crotch due to the action of flow vortexes. The front head of dam and upstream corner are the most prone to hazards, and therefore, should be reinforced against scouring in practical engineering.

Key words: root stone lost, dam buttress, Flow-3D, scouring and collapsing, Yellow River buttress