Study On Submerged Floating Tunnel Characteristics Under the Wave Condition

Abstract

Many fixed crossing of waterways has been built, bridge, pontoon bridge, floating bridge, bored tunnels, and immersed tunnels. In the case of long distance between the shores, deep-water, hard sea state, and conventional structures are not feasible. The Submerged Floating Tunnels (SFT) is a new concept (Norway, Italy, USA, UK, and Netherlands) for crossing deep waterways. This type of structure can provide a connection for land traffic to strait crossing. SFT consists of buoyant tube and tethers supports from sea bottom. In Japan, investigation on the development of the Submerged floating tunnel's technology has been started from 1990. Conceptual work has been done in Japan at Hokkaido Funkawan bay, width of waterway 34km long, water depth 100m, significant wave height 9.3m, and significant wave period 13.0sec. The dimensions of the main circular cylinder body of SFT are 11.4m(4 lane car only) and 23.0m(4 lane car and 2 lane railway) respectively. For supporting the tunnels, vertical bottom supports, and combined horizontal and vertical supports are used. This paper deals with the wave force characteristics and dynamic behavior to the tunnels with numerical calculation(2-D) by mean of Boundary Element Method(BEM) and Morison's equation.