Tunnel construction, for an underground traffic tunnel, fills the interior with compressed air to consolidate the base and form it into a concave curve to be covered by reinforced spray concrete

摘要

In the construction of a tunnel (1), to carry traffic, the tunnel roof (2) is laid over the wall of piles (3) through the ground levels (5). The interior (6) of the tunnel is cleared by compressed air (Pi) to remove ground water seepage, and the inner sides are covered by spray concrete with reinforcement to form a concave curved tunnel base (7) which also consolidates the feet of the wall piles. The compressed air is disconnected, and the remainder of the tunnel working is under normal atmospheric pressure, to lay a flat tunnel base over the concave curvature as a double-shell base structure.