RECENT DEVELOPMENTS IN THE STRUCTURAL SYSTEM AND DYNAMIC RESPONSE OF SUBMERGED FLOATING TUNNEL

The submerged floating tunnel (SFT) is a new type of fully immersed structures for crossing, which has a high application prospect in complex bay environment. To understand the dynamic behavior of SFTs under external excitation, the assumptions of dynamics are firstly sorted out. The mathematical models and dynamic research progress of the independent structure and the whole structure of SFTs under general wave current load, traffic load and accidental load are summarized. The factors affecting the dynamic response of the structure, including the geometric parameters, environmental parameters and traffic parameters, are summarized. The results show that the Euler beam model and discrete elastic support beam model are widely used for pipeline models, and that the beam model that ignores the bending stiffness and considers the initial configuration is mostly used in the calculation model for anchor cables. In two-dimensional analyses, the beam model has high accuracy, but few scholars have discussed it in three-dimensional space. Experiments need to consider the applicability of the model, the representativeness of the environment reality and the accuracy of the measurement, and to focus on the similarity, excitation, measurement methods, the initial state of the structure and the inherent dynamic parameters of the whole system. The seismic response has been widely concerned by scholars. Previous studies have generally shown that the seismic response of the structures is generally within the safe range. However, the dynamic response of the structure is greatly increased when the hydrodynamic pressure caused by earthquakes is considered.