通风措施对于改善高桩码头上部结构耐久性的模拟分析

Simulations of High-Piled Wharf Super Structures Based on Ventilation Optimization

摘要:

考虑到近海地区形成的盐雾易于在高桩梁板式码头的梁格空间内聚集，码头上部结构面临严重的大气区锈蚀风险，为从源头上降低锈蚀风险，基于优化结构物通风的思想，运用数值模拟方法构建了多组自然通风和单独设置风道的辅助通风模型模拟实际高桩码头梁格空间流场变化。结果表明，在自然通风组中当遮挡比为1.15时，梁格空间内自然通风形成的流场扰动最弱；针对处于这种不利情况下的码头结构，提出3种辅助通风措施（梁上开孔法、板上开孔法、联合开孔法），对其效果进行了对比。3种措施的开孔半径对梁格内部的空气流通特性变化趋势影响不大；孔径变小会大大降低梁格进风口区域空气的风速；结合施工难度和成本综合分析得知，板上开孔方案最优。

Abstract:

The salt fog originated from offshore zone and was easy to gather in the semi-closed space formed by beams and slabs of pile-supported wharf called gridiron space. It could induce the premature failure of substructure durabilityof the wharf. Therefore, numerical simulations are conducted to construct the natural ventilation models and the auxiliary ventilation models to simulate the spatial flow field changes in the gridiron space. It is concluded that when the shield ratio (defined as the height ratio of the edge stringer to the air inlet) in the natural ventilation group is 1.15, the airflow inside the gridiron reaches the weakest turbulence. Under this condition, three auxiliary ventilation measures are proposed to enhance the durability of the pile-supported wharf. The numerical simulation results show that the opening radius of the three measures have little effect on the variation of the air circulation characteristics in the gridiron space. A smaller aperture will greatly reduce the wind speed in the gridiron inlet area. Considering construction difficulty and engineering cost, the plan for opening holes on the board is the best.