Covering works wall orbicular supporting structure null for tunnel application

摘要

PURPOSE:To keep the circle of a tunnel without reduction of construction efficiency of the tunnel. CONSTITUTION:Two sets of device units 13 provided with a circular body 11 arranged along the inner wall face of a tunnel, and rotary rings 12 which are attached to the upper and lower parts of the circular body 11 and freely rotated around the tangential axial line of the circular body 11 and also freely positioned to contact the inner wall face of the tunnel, are adjacently installed in the axial direction of the tunnel. This pair of device units 13, 13 are connected to each other at the upper and lower parts by connecting members 14. Ropes 20 are fixed to be attracted by a shielding excavator.