堤防决口下游泥沙冲刷的三维数值模拟分析

Three dimensional numerical simulation research of sediment scour in downstream of dike breach

堤防决口水流冲刷将直接影响建筑物的整体安全,基于Flow-3D软件建立了泥沙冲刷的三维数学模型并采用物理模型试验算例进行验证,验证结果表明数值模拟泥沙计算值和试验实测值拟合较好。随后采用所建模型模拟计算了不同型式(矩型、U型、T型、V型)堤防决口的冲刷过程并对计算结果进行比较分析,结果表明堤防决口出口堤脚处水流冲刷泥沙的程度最大,冲坑深度随着河道水流方向逐渐增大,矩型决口下游泥沙冲刷的的范围面最广,冲坑两侧泥沙堆积高度最大;V型决口下游泥沙冲刷的范围最小,泥沙堆积范围最小;U型和T型决口下游冲坑发展较为对称且规律相似,可相互参考分析。

Scour of dike dam-break flow would directly affect the overall safety of the structure. Based on Flow-3D software,a three numerical sediment scour model was established and verified with a physical model test example. Verification results showed that the sediment calculated values of numerical simulation were in good agreement with the experimental values. Then scour process of different types of dike,including rectangular type,U type,T type and V type,were simulated by the sediment scour model. Results showed that the greatest scour was near the dike breach,scour depth increased gradually along with the direction of river flow,sediment scour area and packed sediment of downstream in rectangular type dike was maximum. However V type dike downstream was minimum. Development of U type and V type dike downstream scour hole were more symmetrical and similar,thus they could be mutual reference analyze.