The overtopping of the landslide dams was studied by means of theoretical analysis and flume tests. The factors that impact the dam breach were discussed and the fundamental procedure of the dam breach development by overtopping was stated. A new concept “flow depth”das well as the criteriond0/D90was carried out to establish the scales for the flume model.Based on the similarity criterion derived,a series of flume experiments were conducted.The experimental result showed a general agreement with the prototype data which on some degree identifies the rationality of definition of the criterion in the present study.The results could be applied as reference for the subsequent relevant researches.
