Simulation of landslide dam failure due to overtopping considering vertical soil particles distribution

Accurate prediction of potential landslide dam breaches is crucial for timely and effective emergency responses to the resulting flood. Although many models for landslide dam overtopping have been proposed in past studies, most of these models did not consider the heterogeneity of dam materials, which is important in reflecting the erodibility of soil. In this study, a new mathematical model for landslide dam breaches due to overtopping was proposed based on a constructed vertical distribution model of dam particle size. Two real-world dams, the Tangjiashan landslide dam and Baige landslide dam, were used to evaluate the performance of the proposed model. In addition, the proposed model was compared with four existing dam failure models, and sensitivity analysis was conducted on the median particle size and particle size distribution. The results demonstrate that the computational outcomes of the proposed model align more closely with the actual results, indicating that the proposed model outperforms the four existing models in accurately simulating the landslide dam failure process. It also suggests that ignoring the variation of dam material particle size along the vertical direction inside the dam body would increase the prediction relative errors of key breach outcomes.