连续跨河桥梁的河道水动力特性模拟

Hydrodynamic Characteristics of River with Continuous River-Crossing Bridges Simulation

摘要: 本文以安徽省蚌埠市淮河干流的四座连续跨河桥梁为例，使用HEC-RAS建立蚌埠闸下至临淮关上游10 km之间河段的一维水动力数值模型，模拟计算三种设计工况下各桥梁的壅水值及流速值。结果表明：HEC-RAS一维水动力模型能很好地再现连续桥梁的水动力特性过程，河道水位模拟值与实测值的水位误差在1 cm左右，表明该模型能较好反映河道洪水的实际运动情况；四座桥梁的壅水值都随河道流量的减小而减小，三个模拟计算工况下桥梁壅水值在0 m~0.026 m范围内；桥下断面平均流速均大于桥梁上游断面平均流速，断面平均流速的增幅随河道流量的减小呈现出减缓的趋势，断面平均流速增大值均在0.04 m/s以内。

Abstract: This article takes four consecutive river-crossing bridges along the main stream of the Huai River in Bengbu City, Anhui Province, as an example. It uses HEC-RAS to establish a one-dimensional hydrodynamic numerical model for the river section between the Bengbu Dam and the upstream of Linhuai Pass over a distance of 10 km, simulating and calculating the water blockage values and flow velocity values at each bridge under three design conditions. The results show that the HEC-RAS one-dimensional hydrodynamic model can effectively reproduce the hydrodynamic characteristics of continuous bridges. The simulated water level in the river channel shows an error of about 1 cm compared to the measured values, indicating that the model can accurately reflect the actual movement of river floods; the water blockage values at the four bridges decrease as the river flow diminishes, with water blockage values under the three simulated conditions ranging from 0 to 0.026 m; the average flow velocity under the bridge section is always greater than that of the upstream section, and the increase in average flow velocity shows a tendency to slow down as the river flow decreases, with increases in average flow velocity remaining within 0.04 m/s.