Experimental Study on the Hoist Tensions Between the Immersing Tunnel Element and Floating Pontoons Under Irregular Waves

Abstract

There are extensive studies on the topic of dynamic interaction between moored floating structures and waves, but the majority of the existing studies concerned the in-place condition of the moored floating system. There are few studies concerned the dynamic response of moored structures during the installation phase, especially for the case of immersion of moored tunnel element. In this study, scale model tests were performed to investigate the motion responses of the immersing tunnel element and hoist tensions between the element and pontoons under random waves. The heave motions of the tunnel were compared under various immersing depths. The comparison showed that the heave of the tunnel element was most severe during the stage of freeboard elimination, which reinforced the conclusion drawn by Song et al. [2014]. The experimental measurements quantitatively clarified the dynamic tensions on the hoist wires between the tunnel element and pontoons under different wave climates, immersion depths and negative buoyancy. In addition, with the quantitative information, the study recommends the operational parameters for the tunnel element immersion.

Keywords:

• Tunnel element immersion
• irregular waves
• hoist tension
• freeboard elimination