Naked Science Forum

Non Life Sciences => Technology => Topic started by: razerback on 10/03/2011 13:37:57

Title: How are tunnels through mountains made?
Post by: razerback on 10/03/2011 13:37:57

How do they cut a tunnel through a mountain or under the sea starting at opposite ends yet somehow manage to arrive spot on in the centre ?

Title: Re: How are tunnels through mountains made?
Post by: SeanB on 10/03/2011 19:20:08

Very carefully!

This is the province of the professional surveyor, who takes care to both do the initial surveying, so that both tunnels start in the correct location and in the correct direction and inclination so that they will meet, as well as the continual checking during boring that the tunnels are keeping to the desired route, and that any corrections are going to make the right movement to ensure they meet.

Title: Re: How are tunnels through mountains made?
Post by: imatfaal on 10/03/2011 19:36:45

In the Victorian heyday of tunnel building in the UK - tunnels would be dug from multiple points.  I know this sounds screwy - but to get through a hill, tunnels would be dug from each end and also from shafts that went vertically down (and would later be used as ventilation shafts).  This could multiply the number of faces of digging and speed up the project.  As Sean said above it called for very careful and meticulous surveying and control. 

There was a TimeTeam (channel 4's pop-archaeology) from the site of a Victorian tunnel and the small towns that developed for the navies and diggers.  It might still be available on Channel4's website - worth watching