Experimental Study on 2D Motion Characteristics of Submerged Floating Tunnel in Waves

Abstract

Submerged floating tunnel (SFT) is a new type of transportation infrastructure for crossing sea straits in relatively deeper water. Compared with the fixed tunnel, the main challenge in designing a SFT is the stability maintaining in a complex hydrodynamic environment, especially for the wave-induced dynamic load. In this study, a series of systematic experiments were conducted to investigate the 2D motion characteristics (i.e., heave, sway and roll) of the SFT exposed to regular waves. The movement of the SFT model is measured by the image processing method which is a noncontact measurement. The experimental observation of SFT motion during the process of wave and SFT interaction is described in detail, and the influence of several governing parameters is thoroughly analyzed, including the wave height and period, submergence depth, buoyancy to weight ratio (BWR), and the mooring line angle. The results show that the motion amplitudes of SFT increase with the wave height increasing. The effect of wave period is related to the natural period of the structure. The sway, heave and roll of the SFT submerged beneath the water surface are much smaller than that of the SFT on the water surface. With the increase of BWR, the motion of SFT decreases. The motion amplitude increases with mooring line angle increasing. Finally, empirical equations are proposed to estimate the motion characteristics of the SFT.

Solution to the traffic problems of long and deep water straits–smart submerged floating tunnel and its research

“…Although in the past decade, scholars or engineers from the world have done a lot of researches and exploration, which includes the preliminary design of engineering structures, the combination of SFT load and limit state design method, mechanical analysis and dynamic response behavior of SFTs and components , fluid-structure coupling mechanism [17,19,[35][36][37], the experimental test and study [35,[38][39][40][41][42][43][44][45][46], the behavior of SFTs under action of accidental load, such as, preliminary studies on vibration response mechanism and prevention measures under general impact load, seismic excitation, explosion and blast impacts and partial failure of anchor cables [4,[19][20][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62], and corresponding construction simulation [63], construction technologies and equipment, durability analysis, smart monitoring and early warning system of anchor cables, SFT and environment [64][65][66]. But the working behavior and mechanism of the SFT under complex sea waters is not very clear, there is a certain distance from making the specification of design and construction methods or guide for SFT etc.…”

Numerical Investigation of Flow and Scour around Complex Bridge Piers in Wind–Wave–Current Conditions

“…Specifically, we maintained a flow depth (h) of 10 cm and focused on clear-water scouring phenomena around the pier by monitoring temporal variations in scour depth. More details regarding the flume and equipment can be found in previous studies by Li et al (2020) [33] and Yang et al (2020) [34].…”

Parametric Study on Mooring System Design of Submerged Floating Tunnel under Extreme Wave and Seismic Excitation

“…Li et al [20] studied the pressure characteristics of different tunnel shapes with pressure sensors around SFTs. Yang et al [21] conducted parametric studies with varying factors, such as BWRs, water depths, wave heights, inclination angles of mooring lines, and wave periods. In addition, Oh et al [22] carried out a scaled-down experiment considering the BWR, water depth, and mooring line shape, and its experimental result was compared with a numerical simulation [5].…”