ANALYSIS OF THE TUNNEL IMMERSION FOR THE BUSAN-GEOJE FIXED LINK PROJECT THROUGH SCALE MODEL TESTS AND COMPUTER SIMULATIONS

In Korea a four lane motorway is constructed between the city of Busan and the island Geoje, reducing traveling times from 1 hour by ferry to just 10 minutes by car. The so-called Busan-Geoje Fixed Link consists of 2 cable-stayed girder bridges and a tunnel, crossing the bay of Jinhae. The submerged tunnel is built by transporting each of its 18 elements below 2 pontoons from a construction dock to their final positions and lowering them on the sea bed. The project is unique, because the tunnel elements are installed in a bay with direct access towards open sea. For this reason, the effects of incoming swells and wind seas were investigated in detail, so that the operational limits of the tunnel element immersion could be accurately determined. This was achieved by using an approach of combined hydrodynamic scale model tests and time-domain computer simulations.