| 摘要 |
<p>Process for the manufacture of a prefabricated concrete arch unit comprising two cylindrical curved faces (11, 12) and at least four side faces (13, 14, 15, 16). According to the invention the arch unit is cast upright on one of its side faces (15) which corresponds to the bottom (35) of the mould, so that the two outer (11) and inner (12) faces of the arch unit (1) are coffered directly on two side walls (31) (32) of the mould, which are given a corresponding curvature and, at the end of the casting, at least one plate (5) is placed in the casting opening (30) and is held, during the casting, in a specific position in relation to the mould, so that the said plate (5) thus sealed forms, after demoulding, a distribution sole plate embodying a reference support plane obeying the geometry to be imparted to the arch unit (1). The invention applies especially to the production of tunnels of large dimensions. <IMAGE></p> |
