Application of HEC-RAS Model for Evaluation of Flood Control of Mijiang Super-long Bridge

This paper introduces the basic principles and main procedures of the HEC-RAS model in calculating the bridge backwater.The HEC-RAS model is then used in the calculation of the Mijiang super-long bridge backwater at the Jilin-Hunchun high-speed railway for passenger traffic.Different scenarios of the frequency of flood events are simulated,including once in 300 years,once in 100 years,once in 50 years,once in 20 years,and once in 10 years.The river water surface lines before and after the bridge construction are simulated under the different scenarios of flood events,and thus the block water height and backwater height of the Mijiang bridge are obtained.The results show that the HEC-RAS model is convenient and practical in analyzing and calculating the effects of the bridge backwater height,and it has engineering applicability and can provide reliable references for decision-making in flood control projects.