基于MIKE 21数值模拟实际砾石滤床通流特性:以汉中市某河道生态修复项目为例

THROUGH-FLOW CHARACTERISTICS OF GRAVEL FILTER BED OF AN ACTUAL RIVER COURSE BASED ON NUMERICAL SIMULATION OF MIKE 21: A CASE STUDY OF ECOLOGICAL RESTORATION PROJECT IN A RIVER COURSE IN HANZHONG CITY

为探究实际砾石滤床应用于河道水修复的效果,以陕西省汉中市某河道为研究对象,采用MIKE 21软件构建了河道的水动力模型。通过模拟在设计流量下主河道与砾石滤床的流动状况,获得河道的流速及水位分布,进而计算获得砾石滤床的通流特性。结果表明:根据流量的分配关系,得到进入砾石滤床的水量仅占河道设计水量的(1.00±0.25)%,因此,砾石滤床在实际河道水体修复中发挥的作用有限。研究认为,实际河道修建的砾石滤床是具有旁路系统的复杂滤床系统,因而在设计中应综合考虑水力停留时间、滤床的通流次数及河道的通流能力,这一结论对研究类似体系具有一定借鉴意义。

In order to explore the through-flow characteristics of gravel filter bed( GFB) in river water restoration,a river ecological restoration project in Hanzhong,Shaanxi Province,was taken as an objective case,and the hydrodynamic model of the river was constructed by using MIKE 21 software. By simulating the flow conditions of the main channel and GFB under the designed flow rate,the velocity and water level distribution of the channel were obtained,and the flow characteristics of gravel filter bed were calculated. The results showed that according to the distribution of flow,the water flow that entered GFB only accounted for( 1. 00±0. 25) % of the designed flow in the river. Therefore,GFB played a limited role in river water restoration in practice. The study suggested that GFB built in a real river channel was a complex system with bypass system. So,hydraulic retention time,flow times of filter bed and flow capacity of river channel should be considered comprehensively in design,which had certain significance for the similar project cases.