植草沟径流调控效果对关键设计参数的响应规律模拟

Simulation of response law for control effect of runoff control at grass swale to key design parameters

为分析道路低影响设施植草沟主要设计参数对地表径流调控作用的影响规律,应用一套耦合了水文和水动力过程的数值模型,研究各设计参数对植草沟径流控制作用的调控效果,经验证模型模拟精度可满足研究要求。模拟结果表明:植草沟具有削减洪峰洪量、推迟峰现时间的作用。且溢流井位于入水口上游侧,横、纵坡坡度越缓时,植草沟径流控制效果越显著。溢流井位置改变时径流控制效果差值达2%~10%,峰值削减差异为13%~28%;横坡坡度从1/3~1/7变化时,径流控制率提高4%~13%,峰值削减效果提升6%~23%;纵坡坡度从0.5%~0.3%变化时,径流控制率提高7%~16%,峰值削减效果提升12%~29%。数值模拟得出各设计参数的影响规律,可用于指导植草沟的规划设计,为其推广应用提供参考。

As one of the effective Low Impact Development measure,the grass swale has been widely used in road construction. In order to analyze the grass swale effects on the surface runoff control under different design parameters,a numerical model coupled hydrology and hydrodynamic processes is used. The reliability was verified against the measured runoff process. The simulation results show that grass swale plays an important role in reducing flood peak and delaying the peak time. The runoff control rates are more significant for grass swale with gentler transverse and vertical slops,and the overflow well located on the upper reaches of the flow inlet. Moreover,when the position of the overflow well varies,the runoff control rate and the flood peak reduction can be changed by 2 % to 10 % and 13% to 28%,respectively. If the transverse slope changes from 1/3 to 1/7,the runoff-control and flood-peak reduction rates can be increased by 4 %-13 % and 6 %-23 %,respectively. Besides,the runoff-control and flood-peak reduction rates are respectively improved by 7 % to 16 % and 12 % to 29 %,as the vertical slope changes from 0.5 % to 0.3 %. The conclusions obtained from numerical simulations provide design guidance of the grass swale and further widen the application.