Submerged floating tunnel (SFT) needs to be fixed or controlled in expected position by its supporting system which can be classified into two types: tension tendon or catenary mooring-line. The later one, catenary mooring-line, is often used for floating body due to its lower cost and easier installment. In this paper, the dynamic behaviors including inertia and hydrodynamic damping of the mooring-line are considered compared with the quasi-static method where only the static restore force is involved, and the nonlinear dynamic response model of the mooring system is developed based on finite element simulations. The influences of the amplitude and frequency of SFT motion, along with mooring-line's structural parameters, on mooring line's displacement and dynamic tension are studied. Also, the taut-slack phenomenon caused by inertial force and hydrodynamic damping is analyzed. Our results shows that when the motion of the SFT is smaller, the dynamic response of the mooring-line is a stable stand wave, and the value of dynamic tension due to dynamic characteristics is about 20% of the quasi-static method, and the tension amplitude difference is around three times larger than the quasi-static method. As SFT movement get larger, the dynamic tension corresponding is about 30% higher than the quasi-static tension. When the mooring-line becomes slack, the response is characterized as travelling wave. The magnification factor of top tension caused by mooring-line's dynamic behavior drops with increase of mooring-line mass density but rises with the increase of the initial tension ratio. (C) 2016 The Authors. Published by Elsevier Ltd.
