2000 Volume 10 Pages 95-100
Ome-Tunnel has the maximum excavation cross section of approximately 260m2, which is quite large for a tunnel constructed directly under downtown area. Since numerous lifeline facilities are buried above the tunnel, the effects of construction on such facilities or nearby buildings have to be kept as small as possible. In order to meet this requirement, we have applied the horizontal-jetgrouting to minimize the surface settlement above the tunnel. The excavation of second bench of upper half of this tunnel has been finished so far and it has been proved, based on our measurement results, that this method is very effective to reduce the surface settlement. For example, the settlement after the excavation was 10-20mm for the grouted area while it was 20-40mm for the non-grouted area.