非黏性堤防溃口发展过程计算模型

Breach Development Model of Non-cohesive Embankment

堤防是防洪工程体系的重要组成部分,一旦发生溃决将可能带来严重灾害损失,明确堤防溃口发展速率与水力要素之间的关系对于预测堤防溃决过程和洪水演进具有重要意义。通过对系列非黏性沙质堤防溃决试验结果进行整理分析,得到溃口垂向下切速率、横向展宽速率与溃口流量、溃口单宽流量之间的关系。结果表明:堤防溃口发展主要存在垂向冲刷、横向扩展2种形式;溃口发展速率与溃口流量呈正相关,但受入流流量影响,没有适用于所有工况的关系表达式;溃口发展速率与溃口单宽流量间的关系基本不受入流流量影响,下切和展宽速率与溃口单宽流量呈现指数关系;基于此关系,构建了以溃口单宽流量为参数的溃口发展过程计算模型,并对溃口垂向下切、横向展宽发展过程进行了模拟计算与对比分析,结果显示模拟情况与真实的溃口发展过程吻合较好,说明所提出的计算模型科学合理,且计算过程简洁。

Embankments play a vital role in flood control engineering systems,and any breach in these embankments can result in severe disaster losses.Therefore,it is crucial to understand the relationship between the development rate of embankment breaches and hydraulic factors to accurately predict breach processes and flood evolution.By analyzing experimental data from series breach tests of non-cohesive sandy embankments,we obtained the relationship between hydraulic factors(discharge and unit-width discharge)and breach development rates(transverse widening rate and vertical down-cutting rate).Findings reveal two major developments of breach,namely,transverse widening and vertical down-cutting.Breach discharge rate is positively correlated with breach development rate,although the specific relationship depends on inflow conditions,making it difficult to express uniformly for all experimental scenarios.Nonetheless,an exponential relationship exists between unit-width discharge and breach development rate.Based on this relationship,a calculation model is established with unit-width discharge as a parameter to simulate and analyze the development process of breaches,including transverse widening and vertical down-cutting.The results demonstrate a strong agreement between the simulated situation and the actual breach development process,thus confirming the accuracy,scientific validity,and simplicity of the calculation model.