Contour shape optimization of the submerged intercrossing water obstacles

Abstract

The submerged floating tunnel (also SFT from the English Submerged Floating Tunnel) is an innovative solution for crossing large water areas with significant depths. The structure has a number of advantages compared to traditional solutions, such as cable-stayed and suspension bridges, an underwater tunnel made of immersed tubes, as well as a traditional tunnel. The main advantages are the ability to cross water obstacles with depths significantly exceeding the record values for bridges (60 m), as well as compensation of loads from its own weight by Archimedean force to ensure positive buoyancy. At the moment, not a single project has been implemented due to serious scientific problems, but the concept is attracting the attention of researchers from different countries, since the need for such structures will increase due to the need to reduce the time of transportation of bulk cargo on transcontinental routes. During operation, SFT structures are subject to various types of influences, including the effect of currents on the tunnel stiffening girder. Thus, the SFT contour shape has a key effect on the nature of the tunnel interaction with the current and determines the external forces that arise (drag force FD and ascending forces FL). The optimal SFT contour shape from the view point of interaction with the current allows one to predetermine the favorable operation of the structure under given conditions. In this article, the current impact on the SFT stiffening girder was assessed using a software package and the girder shape was optimized using gradient optimization capabilities. The article is part of the author’s dissertation research.