基于MIKE 21模型与经验公式在桥梁防洪评价中壅水计算的对比分析

Comparative analysis of backwater calculation in bridge flood control evaluation based on MIKE 21 model and empirical formula

本文以盐城市南环路通榆河大桥工程为例,运用MIKE 21软件对建桥前后水位变化情况进行数值模拟,并将计算结果与《公路桥位勘测设计规范》《铁路桥梁检定规范》中推荐的经验公式计算结果进行比较分析。结果表明:本文研究工况条件下采用《公路桥位勘测设计规范》经验公式壅水计算值与模型计算值基本一致,而《铁路桥梁检定规范》经验公式壅水计算结果明显偏大。因此,在区域水文、河道等资料满足要求时,建议采用数学模型计算壅水值;在应用经验公式时应采用多种规范类公式相互验证,以提高桥梁壅水计算的可靠性。

Taking the Tongyu River Bridge project on the South Ring Road in Yancheng as an example,this paper uses MIKE 21 software to carry out numerical simulation on the water level changes before and after the bridge is built,and compares and analyzes the calculation results by MIKE 21 model with the calculation results of the empirical formula recommended in Highway Bridge Site Survey and Design Code and Railway Bridge Verification Code.The results show that the backwater calculated by the empirical formula of Code for Survey and Design of Highway Bridge Positions is basically the same as that calculated by the model,while the backwater calculated by the empirical formula of Code for Verification of Railway Bridges is significantly larger.Therefore,when the regional hydrological and river data meet the requirements,it is suggested to use mathematical models to calculate backwater value.In order to improve the reliability of bridge backwater calculation,many kinds of formulas should be used to verify each other when applying empirical formulas.