地震作用下海底悬跨管道动水作用力试验研究

Hydrodynamic forces on rigid free spanning submarine pipelines during an earthquake

为了拓展对海底悬跨管道在地震作用下水动力效应的认知,利用水下地震模拟系统开展了刚性管道在地震作用下的水下模型实验.测量了管道周围流场的变化和管道表面的动水压力,并采用Morison方程,按最小二乘原理得出管线的拖曳力系数和惯性力系数,讨论了它们与雷诺数Re、Keulegan-Carpenter数KC、水深及间隙比的关系.通过对试验数据分析得出:Re和KC对管线的受力影响显著;相对于波浪和海流,地震动包含的较高频率会对管道的动水作用力产生重要影响;本次试验工况下,水深和悬跨高度对管道的受力影响不明显.

In order to study the hydrodynamic effects of an earthquake on a free spanning rigid submarine pipeline,a model was tested on an underwater shaking table.The fluid field adjacent to the pipe and the hydrodynamic forces on the surface of the pipe were measured.Hydrodynamic force coefficients such as CD and CM related to the Morison equation were obtained using the least square method.The effects of Reynolds number Re,Keulegan-Carpenter number KC,water depth d and the gap ratio e/D on CD and CM were discussed.According to the experimental results,Re and KC have a remarkable effect on the hydrodynamic forces imposed on a pipeline during earthquakes.Compared with waves and currents,high frequencies are abundant in seismic ground motions,resulting in remarkable effects in the hydrodynamic forces involved.Water depth and span height had no significant influence on the hydrodynamic forces affecting the pipeline in these experimental cases.