Masonry arch for tunnel - has half pipes forming upper bed with joints formed by metal plates and plastics inserts for seals

摘要

The masonry arch for a tunnel is supported on lateral masonry vertical walls of concrete. This is obtained by filling trenches with horizontal pipes to form an upper bed of series of horizontal semi-pipes, parallel to each other. The joints between the semi-pipes are plates, which also form a seal. The plates are metal and welded into position. The pipes have openings on their inner faces and the joints are led to the inside of the pipes which can then butt together. Plastic inserts are used between pipes to give sealing against water.