The concept of Submerged Floating Tunnel (SFT) represents an ambitious solution for crossing wide and deep-water bodies. The potential of building it boasts numerous advantages, such as structural efficiency through use of buoyancy, flexible tunnel alignment, minimised aesthetic impact due to submergence, and even the capacity for relocation. With the pressing demands from population growth and climate change, sustainable offshore infrastructure development is becoming increasingly vital in this new era of the blue economy and the SFT can serve as a critical link for transporting people, goods, and materials. However, construction methods for SFTs remain under-studied. This study presents a systematic approach for the construction of a tether-supported SFT under Kanas Lake, crossing a length of 1.8km. The novel construction includes six components: 1) a semi-floating production flowline for speedy manufacturing of the main structure and minimal land usage, 2) the deployment of open-caissons for reliable tube rootings and novel shoreline connections construction, 3) the use of concrete "sinking vessels" for environmental-friendly construction of gravity anchors, 4) a step-by-step construction friendly plan to navigate the challenges of tube-shore connections, tether pre-tensions and system transfers, 5) construction rigs assembled by portable steel pontoons to eliminate the need for building and using the large onsite facilities, and 6) practical considerations concerning weight design and a solid-water ballast system. Further, quantities, schedules, and critical paths are developed. It is mainly concluded that the work can be completed in two years with minimum impact on the environment. The study offers a valuable showcase on how to build an SFT.
The escalating global population, coupled with rising sea levels and increasingly frequent extreme weather events due to climate change, foreshadow an imminent shortage of food, energy, and living space. In response, offshore energy production, aquaculture farms, and floating cities have emerged as critical areas of research and potential solutions. Serving as fixed links between these offshore structures and the shorelines, Submerged Floating Tunnel (SFT) plays an indispensable role.
