What is Tunnel construction?
'''Tunnel construction''' is an part of [[engineering]] which is about buliding [[tunnel]]s. There are different ways to do this: *If the tunnel is not deep underground, the simplest way to construct it is an '''open put'''. A hole is dug, and the walls at the side are built. At the end, the tunnel gets a roof. *An alternative to this is to first bulid the walls and the roof, and then remove the material as needed. This is also known as '''cut-and-cover'''. *Especially when building tunnels in mountains, or deeper underground there are special [[tunnel-boring machine]]s. They bulid tunnel with a cicular cross-section. {{stub}} [[Category:Engineering]]