张力腿式水下悬浮隧道地震响应模拟——以琼州海峡跨海隧道工程为例

Seismic Response Simulation of Submerged Floating Tunnel with Tension Legs:A Case Study on the Qiongzhou Strait Crossing Tunnel Project

悬浮隧道受水深、海底地形地貌和地质条件的影响小,同时其造价也比深埋隧道和沉管隧道的造价更低,但需要突破相关技术难题。以琼州海峡跨海隧道工程为例,考虑地震引起的水动力荷载、自重、浮力等的共同作用,进行悬浮隧道结构静载分析和动力响应分析等研究,并结合Rayleigh阻尼方程和Morison方程对悬浮隧道附加阻尼的计算进行初步探讨。结果表明:静力分析时,最大截面弯曲正应力出现在两端与岩层嵌固处的底板;动力时程分析时,在地震波的影响下,X方向(轴向)的位移比Y、Z方向的位移都大;张力腿式悬浮隧道在地震作用影响下拉索最容易出现问题,因此为确保悬浮隧道结构的稳定性和安全性,系泊体系中拉索的动力性能需慎重考虑。

Submerged floating tunnels(SFTs)are less affected by the depth of water,undersea topography and geological conditions,and are less costly than deep-buried tunnels and immersed tube tunnels.However,there are still major technical problems to be overcome for their better application.This paper uses the Qiongzhou Strait crossing unnel project as a study case to conduct an analysis of the static load and dynamic response of SFT structures,taking into account the joint action of earthquake-induced hydrodynamic load,dead weight,buoyancy and other loads.Furthermore,this paper also integrates the use of the Rayleigh damping equation and Morison equation to carry out a tentative study on the calculation of additional damping of SFTs.The results show that,in the static analysis,the maximum cross-sectional bending normal stress occurs at the bottom plate where the two ends are embedded with the rock formation,while in the dynamic time-course analysis,the displacement in the X-direction(axial)is larger than that in both the Y-and Z-directions under the influence of seismic waves;As SFTs with tension legs are most likely to have problems with the cables under the influence of seismic action,it is necessary to pay more attention to the dynamic performance of the cables in the mooring system to ensure the stability and safety of an SFT structure.