青函トンネル本坑最深部施工時の地山挙動と支保効果について

抄録

The Seikan Tunnel was constructed in the weak Tertiary rock beneath the deepest seabed of the Tsugaru Straits. We could clarify the ground behavior during the excavation, and could evaluate the effectiveness of support members through the following research:
(1) The diameter of plastic or loosened zone developed in the grouted zone around the main tunnel was determined by measuring the ground deformation by means of measuring instruments which were set up beforehand from the pilot tunnel.
(2) The effectiveness of support members was evaluated using the following four method: (1) Stress measurement of support members, (2) Deformation analysis by “FEM”, (3) Stability analysis by “the Rabcewicz Theory”, and (4) Analysis of measured deformation.
The results will provide valuable information for the construction of undersea tunnels.