Method for reducing frictional losses in tunnels

摘要

Method for reducing frictional loss in unlined tunnels (6) or other tunnels with a rough wall surface and/or irregular cross section. A flexible or rigid pipe (1) with a cross section (5) similar to or somewhat less than the largest circularly open cross section of the tunnel is introduced into the tunnel and attached continuously or at certain points (2) to parts of the tunnel wall (6). Means ensuring that a superpressure occurs within the pipe (1) relative to its outside during flow are also introduced.