Underground Transit Station Construction in Japan

Technologies used in Japan for constructing underground stations for heavy-rail urban rapid transit systems are described. Two example projects have been chosen that illustrate different approaches which incorporate several advanced engineering features. These examples illustrate the top-down, or reverse construction method, secant-pile walls, and underground mining of stations in soft ground. With higher direct costs and longer durations, the methods discussed here will not offer solutions to all U.S. station construction projects. Nevertheless, there is a lot to be learned from the Japanese about working on congested sites in urban areas, particularly under the tough geotechnical conditions in Japan. Considering total costs, including disruptions to commerce and traffic in urban areas, the bad publicity, loss of citizen and political support, litigation and other factors that are increasingly encroaching on United States construction methods, it is argued that Japanese construction methods might provide attractive alternatives.