CFT 2 2 2 Double order system adjusting horizontal length of steel pipe supporter in the tunnel and the structure of the pipe supporter and method constructing thereof

摘要

The present invention relates to a system to dualize steel-timbering through a length-controllable steel girder, and a CFT steel girder with enhanced filling and stiffness. As a horizontal length of a half-sectional steel girder of an arch part is expended and adjusted through a horizontal length adjustment pipe (P) of a horizontal length expanding part (S) of a ceiling crown (C); the present invention is capable of minimizing a gap between the ground in a tunnel in which an excessively excavated part is made and the half-sectional steel girder of the arch part which is horizontally moved to the excessively excavated part. As the half-sectional steel girder of the arch part is horizontally moved to the ground in the tunnel through the expansion and adjustment of the horizontal length, the present invention is capable of minimizing an excavation gap between the ground and the half-sectional steel girder as well as minimizing a quantity of shotcrete to be placed, which is high-priced; thereby achieving tunnel construction economically.