METHOD OF ENLARGING TUNNEL

摘要

PURPOSE:To construct an enlarged tunnel without interruption of traffic. CONSTITUTION:The inner wall of an existing tunnel 1 is reinforced by reinforcing members 3. Anchors 4 are driven from the lower half of the existing tunnel 1 into the ground 2 to unify the ground 2 with the existing tunnel 1 and retain the strength of the existing tunnel. The ground of the upper half of existing tunnel 1 is excavated and after the tunnel wall 7a of the upper half has been formed, the ground of the lower half of the existing tunnel 1 is excavated and the tunnel wall of the lower half is formed to construct the enlarged tunnel. Accordingly this method does not cause evil influences on the inside of an existing tunnel and also the traffic in the existing tunnel is not interrupted.