ABSTRACT
Suzuka tunnel was first bored by 5 m in diameter TBM and was enlarged to about 250 m2. The tunnel of 17 m diameter was designed to pass through under Sosorogawa River and the crown of the tunnel is less than 15 m below the bottom of the river. The tunnel excavation may cause rock mass instability in the area and the change of groundwater flow condition could lead to flooding. If any action was not taken, collapse of the tunnel would give considerable impact to the river flow that is important for agriculture in the local society.
It was expected in this case that the conventional support design would not be adequate to prevent the 3-dimensional rock failure because of complicated geological condition such as Tertiary sedimentary rock with faults. The keyblock analysis was proposed to predict the rock fall and failure in complex situation and even was extended to take into account enlargement sequence of the tunnel.
This paper summarizes a research that aimed to develop an integrated technology for controlling civil works in/on discontinuous rock masses, which covers processes from survey, analysis to measurement and combines a block analysis-based design technique with a rock behavior monitoring technique using digital photogrammetry.
