基于 MIKE21 的河底膜袋砂对河道行洪的影响分析

Analysis on Impact of River Bottom Membrane Bag Sand on River Flood Discharge Based on MIKE21

摘要:

为分析宁芜铁路下穿秦淮新河隧道工程施工期河底铺设膜袋砂对河道行洪的影响程度，利用MIKE21构建水动力模型，对工程段河道流场进行数值模拟，分析膜袋砂对河道水位、流速、流向的影响。结果表明：膜袋砂造成的上游水位壅高影响有限，河道流场变化主要局限于隧道附近，流速有所增大，流向变化较小；总体来说，施工期间工程河段整体流态较为平顺，膜袋砂对河道行洪安全影响较小。分析结果可为宁芜铁路隧道设计施工和防洪评价工作提供一定的技术参考。

Abstract:

In order to analyze the impact of river bottom membrane bag sand on the river flood discharge during the construction period of the Ningwu Railway Tunnel undercrossing Qinhuaixinhe River, the MIKE21 is used to build the hydrodynamic model to numerically simulate the flow field of river in the engineering section, and to analyze the impact of membrane bag sand on river water level, flow velocity and flow direction. The results show that the impact of upstream water level backwater caused by membrane bag sand is limited. The changes in river flow field are mainly limited to the vicinity of the tunnel. The flow velocity increases, and the flow direction changes little. On the whole, the overall flow regime in the engineering section during the construction is smooth, and the membrane bag sand has little impact on river flood discharge safety. The analysis results can provide some technical references for the design, construction and flood control evaluation of the Ningwu Railway Tunnel.