沉管隧道管段系泊系统水动力学分析

Hydrodynamic analysis of mooring system of tube section of immersed tunnel

沉管隧道管段系泊系统是管节在安装过程中抵抗水流作用力和提供准确定位的前提保障,而系泊系统下的整体结构运动响应和锚缆受力则影响着施工阶段的安全性和经济性。文章以广州市荔湾区如意坊沉管隧道工程为实例,采用基于势流理论的水动力学仿真软件AQWA进行计算分析。根据实际数据进行结构三维有限元建模,先对系泊系统进行频域分析,再增加时域耦合分析,并考虑JONSWAP波浪谱和水流的共同作用,研究波浪入射角、环境组合方式等因素对该系统下运动响应和锚缆受力的影响。结果表明:管段在低频区域波动较大,随着频率增加逐渐趋于稳定;有效波高对管段运动响应影响较大;该系统下波浪入射角为90°时,锚缆张力出现最大值。

The mooring system of the tube section of immersed tunnel is the prerequisite guarantee to resist the force of water flow and provide accurate positioning during the installation of the tube section,while the overall structural motion response and anchor cable force under the mooring system affect the safety and economy of the construction phase.This paper takes the example of the immersed tunnel project in Ruyifang,Liwan District,Guangzhou City,and uses the hydrodynamic simulation software AQWA based on potential flow theory for calculation and analysis.According to the actual data for the three-dimensional finite element modeling of the structure,the mooring system was first analyzed in the frequency domain,and then the time-domain coupling analysis was added,and the joint effect of JONSWAP wave spectrum and water flow was considered to study the effect of wave incidence angle,environmental combination mode and other factors on the motion response and anchor cable force under this system.The calculation results show that the tube section fluctuates in the low frequency region,and gradually stabilizes with the increase of frequency;the effective wave height has a great influence on the motion response of the tube section;the maximum value of the anchor cable tension occurs when the wave incidence angle is 90°under this system.