1972•Tunnels & tunnellingRequires access
NOVEL SHIELD DEVELOPMENT IN DENMARK
J A Zachariassen
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Abstract
THE ARTICLE DESCRIBES A METHOD DEVELOPED BY THE ENGINEERING DEPARTMENT OF COPENHAGEN MUNICIPALITY, FOR THE CONSTRUCTION OF HIGH LEVEL PEDESTRIAN TUNNELS AS WELL AS DEEP LEVEL PIPELINE TUNNELS. THE METHOD IS BASED ON A NEW TYPE OF TUNNELLING SHIELD WHICH IS BUILT UP OF SEGMENTS WITH JOINTS PARALLEL TO THE TUNNEL AXIS. THE SEGMENTS ARE SUPPORTED BY INNER FRAMES. THE FRICTION ACTING ON THE WHOLE SHIELD MANTLE FACILITATES THE MOVEMENT OF THE INNER FRAME FORWARD WHEN ALL SEGMENTS ARE PUSHED IN THEIR OUTER POSITION. MOVING THE SHIELD FORWARD IS CARRIED OUT BY PARTIALLY MOVING SOME OF THE SEGMENTS, WHICH HAVE CUTTING EDGES ON THEIR FRONT. AS THE SHIELD IS MOVED FORWARD (HYDRAULICALLY ADVANCING 2.5 M WITH EACH STROKE) ROOM IS MADE FOR PLACING A CAST SECTION BEHIND THE SHIELD. USING THIS METHOD OF CONSTRUCTION FOR PEDESTRIAL TUNNELS, TRAFFIC DISTURBANCE IS KEPT TO A MINIMUM. /TRRL/