Ground freezing application in tunnel constructions

This paper is a report on the outline of three ground freezing works in tunnel construction in Japan. In recent years, the shield tunneling method is often used for the construction of most of water supply and drainage tunnels, subways, road tunnels, utility tunnels underground electric power and telecommunication cables, etc. It is inevitable that the shield tunneling method necessitates auxiliary construction methods especially at a time of starting, arrival, inspection, and underground connection of the shield machines. A higher grade of the quality is strictly required for the auxiliary construction method because the depth of tunnel excavation by the shield machine becomes much deeper and the section of shield excavation also becomes much larger, with diameters of more than 14m, as well as greater earth pressure and hydraulic pressure.