A new construction method for a submerged tunnel has been developed. The new method is an application of the launching erection method for a bridge construction technique. Caissons that is an element of a tunnel are constructed at the tunnel entrance, and then they are pushed into the sea. Thus the method does not need huge construction space and navigation restriction. The technical subject of the new method is reduction of launching force. We developed the machine ‘HYDRO SLIDER’ to cut off the friction force. We carried out small and large scale experiments to investigate the problems in practical use of HYDRO SLIDER. The experiments show that HYDRO SLIDER makes possible to reduce the friction force. We also carried out experiments to investigate the wave forces and the fluid forces caused by a cruising a ship. The results show that the wave forces are larger than the fluid forces caused by ship. Finally, the motion of the caissons caused by waves are simulated numerically, and it was found that the motions are negligibly small.
