潮流作用下复合桥墩局部冲刷研究

桥墩冲刷是桥梁水毁的重要原因之一，准确地计算桥墩冲刷深度具有重要意义.为了比较准确地计算桥墩局部冲刷深度，结合某跨海大桥，采用非结构网格技术和大、小模型嵌套的方法建立该大桥海区的平面二维潮流数学模型，采用潮位、流速、流向等实测资料进行验证.在此基础上，对该海区的潮流动力进行了模拟研究，分析了大桥工程对周围海域的潮流动力影响，并采用我国行业标准推荐的2种公式以及美国现行规范推荐的公式计算多座跨海大桥桥墩的局部冲刷计算.结果表明:大桥工程对桥区附近水域流速和潮位影响不大，桥墩可能发生最大局部冲刷深度的位置均位于主墩深槽附近.

Local scour of composite piers under action of tidal current

The damage to bridges can be caused by scour around piers， so a more accurate calculation of pier scour depth is of great significance. In order to evaluate the scour depth accurately， unstructured grids are used and large and small models are nested to built a two-dimensional hydrodynamic numerical model. This model is calibrated using the measured tidal levels， current speed and current direction data. On this basis， the tidal power in the sea area is also studied， and the influence around the bridge project is analyzed， and the local scour of many cross-sea bridge piers is calculated by introducing some reliable formulas， which are the pier local scour formula 65-2 and the modified 65-1， the existing norms recommended in China， and the formula HEC-18， recommended in USA industry standards. The results show that the construction of bridges has a little impact on the tidal current in the bridge area and the the largest possible local scour depth occurrs in the main pier of the main bridge.