Numerical Simulation Of Hydrodynamic And Structural Response Characteristics Of Submerged Floating Tunnel Under The Action Of Focused Waves

In recent years,with the development of the coastal economy,the construction of marine structures has gradually developed into large-scale,refined,specialized,and deep-water structures.In order to ease the traffic pressure in coastal areas and adapt to complex deep waters,scholars have proposed the design of a submerged floating tunnel(SFT).Compared to traditional modes of transportation,submerged floating tunnels have significant advantages.However,in the complex marine environment,submerged floating tunnels are extremely vulnerable to the action of strong nonlinear waves in the ocean,which can easily cause the structural response of the submerged floating tunnel system and pose a potential threat to the safety of the tunnel.As a kind of strong nonlinear wave,extreme wave has the characteristics of high wave height,sudden occurrence,concentrated energy and extremely strong destructive power,which has a great destructive effect on marine structures.Since the focused wave formed by the focusing of random wave groups in the ocean at a specific position and time is one of the important mechanisms of extreme waves,the hydrodynamic and structural response characteristics of submerged floating tunnels under the action of focused waves are studied to optimize the design and engineering construction of submerged floating tunnels.It has certain reference significance.In this study,a high-precision numerical wave flume is established by numerically solving the governing equations of the incompressible two-phase flow using the high-precision finite volume method.The spring-mass-damping system of the dynamic response of the submerged floating tunnel under wave loads is numerically calculated by using the overset mesh technique and the fourth-order Runge-Kutta method.In this paper,the wave-making ability,the ability to calculate the hydrodynamic load and the ability to simulate the structural response of the structure of the numerical model are firstly verified.Finally,based on the verified model,reasonable calculation conditions are set,and the effects of effective wave height,water depth,spectral peak period,submerged water depth,pipe diameter,anchor cable angle and anchor cable arrangement on the hydrodynamic and structural response of submerged floating tunnel are systematically analyzed.The results show that:the numerical model established in this study can better simulate the interaction between the focused wave and the submerged floating tunnel with high accuracy;Under the conditions of different effective wave heights,water depths,spectral peak periods,submersion depths and pipe diameters,the circumferential pressure distribution of the submerged floating tunnel section is basically the same,but the values are different,especially under the conditions of different wave heights and submersion depths;with the increase of the effective wave height,the hydrodynamic load on the submerged floating tunnel increases gradually,the structural dynamic response is gradually enhanced.At the same time,the horizontal hydrodynamic load on the submerged floating tunnel is easily affected by the change of the effective wave height.And the structural displacement in the horizontal direction of the submerged floating tunnel is much larger than that in the vertical direction.In the range of the studied spectral peak period,the influence of water depth on the hydrodynamic and structural dynamic response of the submerged floating tunnel is very limited;In the range of the studied spectral peak period,the maximum hydrodynamic load and motion displacement of the submerged floating tunnel both reach their maximum values when Tp*=3.759;With the increase of submersion depth,the wave load on the submerged floating tunnel gradually decreases,and the dynamic response of the structure gradually weakens;Under the same incident wave conditions,the smaller the diameter of the submerged floating tunnel,the smaller the dynamic response of the structure;Mixed arrangements of anchor cables is more stable than which is inclined.In the range of anchor cable angles studied,the anchor cable angle of 50° is more stable than the anchor cable angle of 75°.