Experimental and numerical studies on landslide dam failure and the induced flood and morphological changes
(2024)
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- Abstract
- Landslide dams are natural dams that are formed by the blockage of a river channel with landslides, rock falls and debris flows. Landslide dams are prone to overtopping failure shortly after their formation, resulting in catastrophic floods in the downstream areas, further posing a great danger to the local residents and altering the local environment. Therefore, it’s necessary to analyze the failure of landslide dams, the induced floods and the morphological changes in the downstream areas. Unlike artificial dams and earthen embankments, landslide dams can be characterized by the following three features: the greater dam width along the river, the widely graded and non-uniform material composition, and the internal multi-layered structure. These three characteristics significantly influence the failure of landslide dams and induced morphological changes, but are rarely considered in current research, especially the latter two of them. The present thesis aims to analyze the failure of landslide dams, as well as the induced floods and morphological changes, from both experimental and numerical points of view, taking into account the aforementioned three characteristics of landslide dams. The study starts with a field investigation and case study of the two Baige landslide dams that occurred on the border of Tibet and Sichuan Province, China, in 2018. A simplified physical based numerical model is also used to analyze the floods and their impacts in the downstream areas. Second, a series of experiments considering widely graded and non-uniform sediments are carried out to analyze the influence of both the dam and movable bed materials on the dam failure process and the induced morphological changes. Third, a numerical model considering the non-uniform and multi-layered sediments is developed based on the shallow water equations, modified Exner equations and Hirano’s active layer equation. The applicability and accuracy of the model are further verified by two experimental tests considering both uniform and non-uniform, single-layer and multi-layer sediments. Finally, the proposed numerical model is further applied to simulate the failure of the Baige landslide dam, as well as the induced floods and morphological changes. The numerical results are again compared with both the observed data and the results obtained by the simplified physical based numerical model.
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Yang, J. (2024). Experimental and numerical studies on landslide dam failure and the induced flood and morphological changes. https://hdl.handle.net/2078.5/243990