Session: 02-01-02 Structural analysis and optimisation 2

Paper Number: 107918

107918 - A Preliminary Study on Design Optimisation of Submerged Floating Tunnels 

This paper reviews the submerged floating tunnel, a concept initially proposed in the 19^th century, only sporadically built, but possibly more viable in the future. A comprehensive literature review on the concept of submerged floating tunnels is initially presented, with the current knowledge of conceptual options for plane and vertical alignment, shore connections, cross-sections, mooring lines, anchoring systems and pontoon support systems discussed. Potential design options and their features are discussed in terms of the critical parameters such as submergence depth, tunnel cross-section dimension and constitutions, Buoyancy-Weight-Ratio or Residual Buoyancy, mooring line stiffness, and the free vibration frequency of the system. The second part of this paper introduces a multidisciplinary optimisation model for this complex engineering system, with a balanced approach to wave-structure-soil interactions taken. By considering specified environmental constraints (water depth and width and wave characteristics), the minimum cost solution for submerged floating tunnel is used as the target for the optimisation. Optimisation variables including submergence depth, outer and inner diameters of the tunnel, reinforcement concrete densities, mooring line diameters and size of gravity anchor are optimized in an integrated way. A further work plan is discussed that combines advanced geotechnical solutions of the mooring and anchoring design into the optimisation model. This will provide further critical insights into submerged floating tunnel design.

Presenting Author: Wei Lin University of Melbourne

Presenting Author Biography: Wei Lin had ten years of experience building large marine infrastructures, specialised in designing and constructing immersed tunnels and holds international patents as the first inventor of novel offshore/submerged devices and structures. In 2016, He obtained his master's degree in structural engineering and mechanics, jointly awarded by Edinburgh University & Glasgow University. He is now in the second year of his PhD.

Authors:

Wei Lin University of Melbourne
Yinghui Tian Department of Infrastructure Engineering | Faculty of Engineering and Information Technology
Mark Cassidy The University of Melbourne