Design strategy for submerged floating tunnels: Structural response analysis and rational mooring-boundary condition combinations under wave loads

Abstract

This study examines the dynamic behavior of submerged floating tunnels (SFTs) induced by wave action, considering various mooring types and boundary conditions to determine optimal design strategies. The analysis includes three mooring configurations: vertical (Type 1), inclined (Type 2), and combined inclined (Type 3), evaluated under four distinct boundary conditions: free, fixed, hinged, and hinged-fixed. Through a detailed comparative analysis of structural responses under irregular wave conditions, this research reveals the significant influence of both mooring configurations and boundary conditions on the performance of SFTs. Furthermore, the study identifies the optimal combination by analyzing serviceability, strength, and stability criteria. The combination of Type 3 mooring with free boundary conditions proved most advantageous, effectively minimizing displacements, accelerations, and stresses while satisfying all design criteria, even under inclined wave conditions. Furthermore, optimization of the Type 3 mooring was also performed. These insights offer valuable guidance for engineers involved in the design of SFTs.