Investigation of tensile force on mooring line for a submerged floating tunnel

Abstract

A submerged floating tunnel (SFT) is defined as a tunnel that floats by an equilibrium of buoyancy, self-weight and supporting force. With its advantages of safety in critical cases and cost efficiency, there have been increased about research of the SFT recently. In this situation, a calculation of reaction forces acting on its anchor system is important for the design of supporting system, as well as the section design and overall process of structural management. However, it is true that there are only few cases about actual experimental data of the SFT, even from the field-scale tests due to the limitations of materials and constructional technologies, which supports the necessity of numerical analyses. In this research, 200 m-long solid element based SFT model was numerically analyzed for the evaluation of reaction forces on mooring lines, which connects the tunnel module and the anchor system. As a proto type model, a circular section of 23 m outer diameter was assumed refer to the Funka bay SFT, in Japan. In detail, a span length of an SFT module is 50 m and four modules of tunnel were connected in total while the mooring system was linked at each 50 m span length. For the load cases, equivalent static cases such as wave and earthquake were considered. Through the study, the reaction force of mooring lines were evaluated and validated.