Study on Similarity Laws of Model Experiments of Debris Flow Channels

Model experiment of debris flow is one of the important methods for studying debris flow movement and prevention. The similarity laws between model and prototype are very important for the accuracy of experimental results. The geometry similarity, movement similarity and dynamic similarity were discussed first in this paper. Then, three similarity laws, including gravity similarity, resistance similarity and gravity and resistance similarity simultaneously were deduced under the assumption that debris flow was an incompressible fluid. At last, the methods based on triangle, trapezoid and rectangle process for simulating debris flow discharge in model experiments were discussed and compared. Results indicate that if debris flow movement dominated by gravity, the Froude number of model experiment and prototype must be equal. If debris flow movement dominated by viscous resistance, the Reynolds number must be homologous. If debris flow movement dominated by both formers simultaneously, the Froude number and the Reynolds number must be equal. After three discharge similarities between model experiment and debris flow prototype were compared, results indicated that the triangle method and the trapezoid method all have a certain degree of technical difficulty. For the rectangle method, debris flow is supplied based on the maximum discharge in the whole model experiment. Therefore, the experimental results are larger than actual conditions, but for model experiments, it aimed at researching mitigation measures of debris flow, the rectangle method is more appropriate.