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

摘要

Concreting process for the construction of tunnels, characterized in that the annular space formed between the wall of the tunnel and the corresponding parts of formwork, is filled with liquid concrete which drains leading to a premature setting, by means of filters incorporated in the corresponding limiting walls. (Machine-translation by Google Translate, not legally binding)