Abstract: Hydraulic boundary conditions at an embankment breach must be specified to study the mechanism of embankment breaching or breach repair technologies, but accurate specification of these conditions is difficult due to incomplete measured data and the complexity and disparity of a real breach. In this work, we collect and analyze 100 groups of prototype data and experimental test data of embankment failure and earth dam failure, and establish the correlation between the parameters charactering the hydraulic boundaries at embankment breaches and supplement the missing values through data correlation and fitting based on a cluster analysis approach. For a generalized typical breach, we obtain its hydraulic boundary parameters and related equations using statistical analysis of the probability density of its dimensionless parameters. The analysis shows that most of the breaches feature with a width of 20-100 m, a water head of 4-12 m, and a mean flow velocity of 2-8 m/s, and that the distribution probabilities of these parameters’ values are all in the range of 64%-71%. The probability densities of both the width-to-depth ratio and flow Froude number of the breach follow the normal distribution; the probability is roughly 55% of the former in the range of 3-8 and 60% of the latter in the range of 0.4-0.8.

Key words: embankment breach, hydraulic boundary characteristic parameters, cluster analysis, missing values, probability density