support device for roadway or tunnel in temporary construction

摘要

The device for provisionally supporting a gallery or a tunnel which definitely shall be supported by support frames closed on all sides comprises a floor girder which servs as a part of the provisional frame as well as of the definite one. For the provisional support said floor girders are laid out separately near the mining face. Only U-shaped elements which are reduceable in profile are to be brought forward through the inner width of the positioned frames. These U-shaped elements may be connected with the said floor girders to form a complete provisional supporting frame closed on all sides. Such provisional support fulfills absolutely the safety requirements, and setting the definite frames may be carried out quickly and without long lasting interruptions of biasing the roof because the provisional floor girders remain usable as floor girders for the definite supporting frames, too.