EXTENSION TUNNEL USING EXISTING TUNNEL CONSTRUCTED ON ROCK AND CONSTRUCTION METHOD FOR IMPROVING WORK EFFICIENCY BY SUITABLE EXCAVATOR

摘要

PURPOSE: A construction method for an extension tunnel using the existing tunnel constructed on rock is provided to improve work efficiency by using a suitable excavator for rock, to prevent the congestion of traffic at an extension work for a tunnel, and to reduce the cost and period of construction by utilizing the existing tunnel. CONSTITUTION: The construction method for an extension tunnel(20) using an existing tunnel(10) constructed on rock comprises the steps of: installing a housing(60) by digging a half length of the housing(60) through the soil on the lining of the existing tunnel(10) using a hydraulic jack gradually; installing an excavator(40) attached with an auger excavator(70) on a support(61) and perforating an unit excavation hole by stage; forming an extension tunnel wall(30) by assembling/installing a reinforcing bar in the unit excavation hole and placing concrete; removing soil between the existing tunnel lining and the extension tunnel wall(30); finishing up an extension work for a tunnel by repeating above steps; and adjusting the road surface and installing lightings in a tunnel.