How would you a destroy a massive (200+ yards) pipe running from the surface to 10 miles underground.?

Question

I'm writing a story! A plot point hinges on coming up with a credible way to destroy these alien structures. The protagonist is a structual engineer. So, the solution should use his background. I don't know what the pipes are made of. If it helps the plot, I could make them out of earth or a synthetic plastic or some strong metal or something not yet invented! Can anyone think of a cool but credible way of destroying these structures? If it helps, the pipes need to be big, but I could scale them up or down if it lent to a more spectacular scenario. Again, I need something based on science. e.g. "The weakest point in the tube would be half way between, blah, blah, blah. So if you had some theoretical explosive device, you could melt....."

Answer 1

Such a large structure would be difficult to destroy. An atomic bomb would probably do the trick, but conventional explosives are pretty much out of the question. The Earth (or whatever planet) support outside of the tube will add greatly to its strength. Even damage from an atomic bomb would be pretty localized. The radiation would probably be more of a hinderance than any physical damage.

OTOH, you might have the Earth/planet itself do the work. If your hero can set a tectonic or volcanic process into motion, that would do the trick. Since you're 10 miles underground, you would be close to magma chambers anyway. Or maybe your hero could flood the tube and add a substance that gels and/or solidifies the water.

Good luck!

Answer 2

It could be done but you might want to consider an alien material like synthetic platics as they are often very strong but can also be brittle. (e.g. carbon fibre with a small number of cross weaves) That sort of stuff would propably shatter

A lot of explosive use shockwaves to do the real damage, I like what you put about it being halfway down, as that would give the blast an equal chance of destroying the whole pipe.
although many readers would expect the military to have though of that, have you considered shielding the exits, and having him find a way through?

Plastice explosives are the most powerful stuff you character could get his hands on, he could use a type of shrapnel as well to kill anything trying to come up and stop him.

F.Y.I.
the commom explosive C4 is not normaly called C4 by explosive technichians they have renamed it P4, I think this is to differentiate it from the bad rep its gotton,
An also c4 can only be detonated properly by an electronic surve.

Either way you should consider the blast wave when you describe the explosion, the plasma/gass shoot out the opening after an explosion that big as it got nowhere elce to go.

Hope that helps, i'm realy interested in this sort of stuff if youve got any more questions, email me and i can help out.

Answer 3

If you want to be realistic, a pipe that size would not be demolished. Large pipes in practice are abandoned in place. Which means that both ends are plugged up and what is in between is left there.

Short of nuking this structure, you might just have to blow up the end of this tunnel, but then you are set up for the sequel.

Answer 4

Alternate approach:

With access to enormous amounts of electricity, a steel pipe could be melted as in electric arc furnaces. "...the theoretical minimum amount of energy required to melt a tonne of scrap steel is 300kWh (melting point 1520°C/2768°F)."
http://en.wikipedia.org/wiki/Electric_arc_furnace