ABSTRACT
The underground railway project progresses to relocate the operating railway on the surface in Yokohama city of Metropolitan area. Especially in soft ground with shallow cover, tunnel is excavated by shotcreting method, and various auxiliary measures and monitoring control system are employed because of the need to secure operating track during the excavation. This Line is a major trunk railway line that has over one million passengers per day, connecting Tokyo and Yokohama. In this relocation project, an approximately 2 km long section near Yokohama station, is being relocated to underground railway to enable through train service with the new subway line. The construction of underground relocation is being performed by shotcreting method as selected by considering the topography, geology, depth of cover, and adjacent structures in each section. This paper describes overall planning, design and construction of the urban tunnel just beneath operating railway.
