ABSTRACT
New underground infrastructures in Greater Tokyo in Japan are now planned through greater depth space where the sedimentary soft rocks (mudstone) are widely distributed. The sedimentary soft rocks have the strain and confining pressure dependency as deformation characteristics and creep deformation is observed, however, the measurements of detail deformation characteristics of ground during tunneling the sedimentary soft rocks are not enough. This paper describes the test results carried out a following experiment, excavating an unsupported horseshoe-shaped tunnel with 5.0 m in height in the sedimentary soft rocks at a depth of 45 m to obtain basic data on the ground deformation characteristics and deformation behavior of the ground around the tunnel, and the ground deformation during tunnel excavation works by relating to the deformation characteristics and features of sedimentary soft rocks are reported.
