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
E21D11/15—Plate linings; Laggings, i.e. linings designed for holding back formation material or for transmitting the load to main supporting members
E21D11/155—Laggings made of strips, slats, slabs or sheet piles