After collecting and analyzing the data of existing dam failure cases summarized in foreign references,as well as extra cases in China,a basic database containing 154 dam breaching cases with detailed information is constructed.Taking dam type,reservoir shape coefficient, ratio of water level to breach depth and dam height,which are all expressed in dimensionless forms,as independent variables into account,the regression analysis is adopted to establish dimensionless formulas for calculating peak outflow discharge,final average breach width and failure time.The new empirical model considers the influences of dam type,failure type,storage capacity,water level,dam height and breach depth.Comparing to the existing models for dam breaching parameters,the present model has the advantage of using larger database,easier acquisition of input variables,and including more influence factors of dam breaching parameters,in particular,the dam characteristics and current hydraulic conditions.Then,for all the dam breach cases collected in the database,the calculation using different models is carried out.The result shows that the present model has better adaptability and prediction accuracy based on the statistics of overall computing error,the value of root-mean-squared error and coefficient of determination,by comparing to the previous models.Furthermore,four typical breach cases of different dam types and failure types are selected to verify the rationality and superiority of the present model,and the calculation results of present model are more accurate in most of the cases than those of the other models.
