RETAINED FORMS FOR CHANNEL FORMATION IN TUNNEL LINING Russian patent published in 2002 - IPC

FIELD: construction engineering; applicable as retained forms in formation of ventilation channels in tunnel lining. SUBSTANCE: forms for formation of ventilating channels in tunnel lining include sheathing members in the form of box and load-bearing frame. Box is made in the form of thin-walled trough open from side of tunnel internal space. Trough side walls have shelves made for installation of their outer surfaces on internal surface of tunnel lining. Load-bearing frame is made of members interconnected with one another by cylindrical hinges and has a cylindrical hinge for connected with tunnel floor. Each member has two longitudinal sheet belts spaced parallel at a distance close to trough width and interconnected with each other by transverse tubular upper and lower ribs for location of upper generator of upper ribs over internal surface of trough bottom, and for location of lower edges of longitudinal sheet belts over internal surface of tunnel lining. Trough walls may be made with stepped shelves. Trough may be made of blocks whose one end face of each block has a pocket for installation of the other end face of next block up to sop. End face of each block is stepped for height exceeding trough thickness. Metal plates are secured to trough bottom and walls. Metal embedded parts may be secured in trough side walls from outer side. EFFECT: reduced weight and cost of forms. 5 cl, 12 dwg