为研究海口市荣山河四线并联斜交桥桥墩河段水动力特性及不同水位下的桥墩-桥梁体系整体的自振特性，应用FLUENT及ANSYS软件，基于分离涡方法（DES法），建立了四线斜交桥河段的河槽水流三维模型，模拟了不同流速和不同斜交角度下的流场分布及流固耦合作用下的桥墩-桥梁体系自振特性。结果表明：荣山河四线并联斜交桥的过流能力可达到400 m3/s，桥下最大壅高为0.69 m，桥下留有一定安全距离；考虑流固耦合作用下的斜交桥墩-桥梁体系满水情况下的自振频率为7.66 Hz，不会与通过列车发生共振危险。

For the study of hydrodynamic characteristics of the bridge pier of the four-line parallel skew bridge of Rongshan River in Haikou City and the overall self vibration characteristics of the pier and bridge system under different water levels, FLUENT and ANSYS software were used, based on the DES method, the three-dimensional flow model was established for the four-line skew bridge river channel , the flow field distribution under different flow rate and different oblique angle as well as the self-vibration characteristics of the pier-bridge system under fluid solid coupling was simulated. The results showed that the maximum flow capacity of the four-line parallel skew bridge could reach 400 m3/s, and the bridge had a certain safe distance, with a maximum backwater height of 0.69 m. The natural frequency of the pier-bridge system under the condition of fluid solid coupling was 7.66 Hz, without the risk of resonance with the passing trains.