Open trench side stiffening, in tunnel construction - involves side girders cantilevered over props, with rear abutment support

摘要

Side revetting walls are mutually stiffened by props built in, as excavation progresses, in a structural cavity, for tunnelling construction, progressively lifted by excavators. In the area being worked by the excavator (4), these walls (1,2) are stiffened by lateral girders (5) cantilevered out across the props (3) already built in. These are braced in their front parts against the revetting walls, and in their rear parts both on abutments (6) connected to the props, and against the walls. Girders are pref. of the lattice type, and may be supported against the walls via interposed hydraulic presses (8), pref. sited in the area of girder hinges (7). Stiffening is simple and economical, and permits unhampered operation of excavators.