ABSTRACT
Underground spaces in Tokyo are congested with subways and vital urban facilities. New subway construction inevitably had to be done in extremely deep or in the close vicinity of facilities. In the central eastern part of Tokyo, cut-and-cover tunneling was undertaken to extend a subway directly under the metropolitan expressway and in a narrow space between caisson foundations. In spite of extremely difficult conditions, namely, very soft ground as well as large critical buried structures and remaining temporary facilities, the tunneling work was completed successfully.
