研究目的：珠肇高铁西江特大桥采用主跨2×435 m三塔斜拉桥方案。为减小中塔弯矩,在中塔塔顶与边塔间布置有加强索。为减小加强索直径并考虑其可更换性,加强索采用平行双索形式。利用双圆柱系统中下游圆柱气动力特性试验结果,通过数值计算方法对不同来流方向风作用下下游加强索尾流驰振振动特性进行研究分析,并提出合适的振动抑制措施。
研究结论：（1）通过数值计算方法对间距比L/D=3.17（L为加强索中心间距,D为索直径）的平行加强索尾流驰振进行计算分析,当平行拉索中心连线与来流方向呈一定角度时,下游拉索所受气动力随空间分布的不均匀性会导致其发生沿环形轨迹运动的尾流驰振;（2）在1.5%阻尼比范围内,单一增加拉索阻尼比不能抑制尾流驰振发生,且对降低尾流驰振振幅十分有限;通过设置辅助索、横向连接杆的方式增加拉索刚度或自振频率可有效抑制尾流驰振发生;（3）本文研究可为采用双排斜拉索或加强索布置形式的斜拉桥设计提供参考和借鉴。

Research purposes: The Xijiang Super Major Bridge of Zhuhai-Zhaoqing High-speed Railway is a cable-stayed bridge with three towers and a main span of 2×435 m. To reduce the bending moment of the middle tower, reinforcing cables have been set up between the top of the middle tower and the side tower. To reduce the diameter of the reinforcing cables and consider its replaceability, the reinforcing cables is in the form of parallel double cables. Based on the experimental results of the aerodynamic characteristics of the downstream cylinder in the double cylinder system, the study and analysis of the characteristics of wake-induced vibration of the downstream strengthened cable under wind action in different inflow directions are carried out through numerical calculation methods, and appropriate vibration suppression measures are proposed.
Research conclusions: (1) Numerical calculation method was used to analyze the wake-induced vibration of parallel reinforced cables with a spacing ratio of L/D=3.17 (L is the distance between the center of the reinforced cable and D is the cable diameter). When the central connecting line between parallel cables is at a certain angle to the incoming flow direction, the wake-induced vibration along a circular trajectory will be caused for the uneven spatial distribution of the aerodynamic force of the downstream cable. (2) Within the range of 1.5% damping ratio, simply increasing the damping ratio of the cable cannot suppress the occurrence of wake-induced vibration, and has limited effect on reducing the amplitude of wake-induced vibration. By setting auxiliary cables and transverse connecting rods to increase the stiffness or natural frequency of the cables, the occurrence of wake-induced vibration can be effectively suppressed. (3) This study can provide reference and inspiration for the design of cable-stayed bridges using double row cable-stayed or reinforced cable.