E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
E21D11/00—Lining tunnels, galleries or other underground cavities, e.g. large underground chambers; Linings therefor; Making such linings in situ, e.g. by assembling
E21D11/14—Lining predominantly with metal
E21D11/18—Arch members ; Network made of arch members ; Ring elements; Polygon elements; Polygon elements inside arches
E21D11/20—Special cross- sections, e.g. corrugated
Assemblage par emboitement de deux profiles a section droite en z, notamment pour la realisation d'une panne, d'une lisse ou d'un support de plancher.