Structural analysis and safety assessment of submerged floating tunnel prototype in Qiandao Lake (China)

This article presents the structural analysis and the safety assessment of the submerged floating tunnel (SFT) prototype, which is designed to be built in Qiandao Lake (China). Based on the principle of bending stiffness equivalence, a homogenized equivalent single-layered-tube model is established. The effective beam bending stiffness and the corresponding Youngrs modulus are deduced. By using lamination theory of composite mechanics, the equivalent local bending stiffness of the SFT prototype panel is calculated and the corresponding modulus is obtained. The moduli deduced via the two approaches are nearly equal. Then, the strength analysis of the SFT prototype under the actions of water wave, water current and earthquake is carried out. The reliability of the SFT prototype is assessed through the comparison of the obtained stresses with the design values.