Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them

Underground or underwater structures; Retaining walls > Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them

underground or underwater structures (underground tanks B65D88/76; hydraulic engineering, e.g. sealings or joints, E02B; underground garages E04H6/00; underground air-raid shelters E04H9/12; burial vaults E04H13/00); Retaining walls > Underground structures, e.g. tunnels or galleries, built in the open air or by methods involving disturbance of the ground surface all along the location line; Methods of making them