Concrete procedure for the construction of tunnels. (Machine-translation by Google Translate, not legally binding)

摘要

Improvements introduced in the object of the main patent no. 395.457 filed on september 27, 1971 by: "procedures of concreting for the construction of tunnels, characterized by the filters to facilitate the rapid setting of the liquid concrete that has to constitute the lining of the tunnel they are concentrated in the pressure ring, giving rise to the premature solidification of a concrete ring, which can serve as a buttress together with the rings that form the formwork, to the pressure ring on which the hydraulic cylinders in charge of the forward movement rest. Of the formwork. (Machine-translation by Google Translate, not legally binding)