土石坝溃坝参数模型研究

Parametric Model for Breaching Analysis of Earth-rock Dam

通过对国外土石坝文献中溃坝案例数据信息进行校验整理,并补充收集到的相关国内溃坝案例,形成了一个包含154个溃坝案例的基础数据库。在此基础上,针对均质坝和心墙坝两种坝型,对模型输入变量进行无量纲化处理,选择库容形状参数、水位比参数及坝高参数等作为自变量进行回归分析,建立了可模拟土石坝溃口峰值流量、溃口最终平均宽度和溃坝历时的数学表达式。该溃坝参数经验模型可反映坝型、溃坝方式、溃坝时库容、水位、坝高、溃口深度等参数对溃口峰值流量、溃口最终平均宽度和溃坝历时的影响。此外,通过对国内外常用的溃坝参数经验模型的统计分析发现,本文模型相较于已有的模型,依据的土石坝溃坝案例数据库信息更为翔实,输入变量较易获取,对溃坝参数的影响因素考虑更加全面,特别是能更好地反映坝体特征和当前水力条件对溃坝参数的影响。针对数据库中的相关案例,使用本文模型与常用经验模型进行计算验证,通过整体均方根误差和可决系数的计算,发现本文模型在整体上具有更好的适应性、计算精度和拟合效果。再基于不同的坝型和溃坝方式,选取4组国内外典型案例进行分析,发现本文模型在整体上计算结果较为准确,进一步验证了本模型的合理性和优越性。

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 fail- ure 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.