关键词: 堰塞坝, 溃决过程, 模拟技术, 大尺度试验, 水沙耦合数学模型

Abstract: Determined by its geometric feature, material composition and reservior capacity, the breaching mechanism of natural landslide dam is rather complex. Finely modeling the breaching processes and accurately predicting peak discharge are foundations and key aspects in support to emergency measures, which are also the research focuses facing demands of national hazard prevention and mitigation. In this paper we systematically review previous experiments and numerical studies on landslide breaching, and conclude that the scale of previous experiments were small and the effect of lake volume was not considered, which failed to model the final shape of breach. Meanwhile, physical mechanisms in the existing numerical models were not complete and thus introducing too much unnecessary hypotheses, which requires further development. Large-scale experiment is proposed to study the breaching mechanism and the process of landslide dam. Coupled hydrodynamic-morphological model is recommended to simultaneously model the whole filed and processes including hydrodynamics in the lake, dam breaching process and propagation of resulting flood in the downstream. The new model abandons hypotheses for discharge, shape, side slope, residual dam height and breaching time, which are instead rendered as part of the model solution. Hence, the modelling capacity and prediction accuracy of landslide dam breaching are expected to be largely enhanced.

Key words: landslide dam, breaching processes, technologies of modelling, large-scale experiment, coupled hydrodynamic-morphological model