The No. 2 Yamate Tunnel was constructed between Motomachi and Sakuramichi-shita as a tram tunnel in 1911, converted into a road tunnel in 1929, and widened by the Messor Method in 1975. It remains a reinforced concrete lining tunnel today. In 1999, damages were reported ranging from cracks, concrete uplifting, concrete peeling, and sinking in some parts of the top crown and along the entire side. Repair work was undertaken with cracks sealed and injection rock bolt used to improve the ground.
Eight optical strands in steel spiral sheath, three temperature sensors and a monitoring station were used during three phases: first, pre-grout monitoring; second, chemical grouting; and the third, post-grout monitoring. As a result of the accuracy and positive performance of the monitoring data from the first reinforcement work, plans for further reinforcement were considered unnecessary and significant additional costs saved.