In science fiction, you’ll sometimes see a vehicle thats designed for tunneling through the ground. These typically have a giant auger at the business end, and tank treads. You see a lot of variations of them, and they seem to go back pretty far (hence the title).
I’m kind of curious how well a drillcar would actually work. I know actual industrial Boring Machines look nothing like one (being a giant cylinder that “shaves” away material in front of it, shoring up a tunnel and carting away stone chips as it chugs along.
Drillcars seemed to mainly be intended for transport, not for tunneling, though. Various works of fiction have them travel surprisingly fast (often dramatically bursting out of the ground). Is this even remotely possible?
Could you design a vehicle capable of traveling through most soils/rock at 50mph? Could some auger-nosed vehicle actually work? What if it wasnt solid rock (which doesnt feel plausible) but rathet soil/sand/gravel?
This would only work if the surrounding material was extremely loose and easily moved, like if you were burrowing through loose sand or powder snow. For actual dirt or rock you won’t be able to push it aside, since there’s nowhere for it to go. You’ll need to somehow transport it backwards and pack it in the tunnel behind you, and that’s only practical if you’re deliberately shaving away a little at a time, like how actual tunnel boring machines work.
In Tom Swift and His Atomic Earth Blaster the problem of what to do with the dirt and rocks was solved by including an atomic pile and something called a “secret activator” which vaporized the rubble and shot it out behind the machine, or so I recall from reading it decades ago.
I suppose it would need to generate enough pressure to compress the medium that surrounded it. Pulverize it to its constituent atoms and leave a sheaf of highly compressed new material?
(This would also solve the problem of what holds the “hole” open after it passes.)
Among all the other problems is the energy source issue, so it would really need to “eat” the rock in front of it, extract the energy, and then “excrete” the molecular detritus.
I think we are starting to see why it hasn’t happened…
Or maybe it has, but they’re just really, really small.
While we might “debate” this, it really does not look lie a Great Debate. And, while it does seem to be soliciting opinions, I really think this would do better in General Questions than in IMHO.
Giant auger-type drilling vehicles are used in coal mining (like this) but you don’t ride inside and they don’t create a tunnel by themselves, they just run along/around and rip up the face (which would be propped up/ rockbolted behind them to create a stope or tunnel). They’re not the usual mining machine, I think they’re mostly used to create accessory shafts, adits and raises that the long-wall and continuous miners are too big for, when blasting (the usual way) is not an option.
Another issue that would kind of make them impossible is the transfer of torque. IOW something would have to hold the prime mover used to turn the ‘drill-head’ of the craft otherwise the bit would simply wedge against the strata and the whole craft would spin (like when a helicopter loses its tail rotor)…
(BTW, I loved Adult Swim’s STRATA or Saul of the Mole Men!!)
It wouldn’t even work for loose sand or dirt - while they may be “loose”, they are not very compressible. When you’re buried in it, you can’t just push it to the side and create a gap.
Even in dirt, the problem is that you can’t even pack loose dirt as well as centuries or millenium of constant pressure.
IIRC in a book about tunnelling out of a German POW camp, they mention one pair who tried to do just that, packing the dirt behind them as they went. They had to surface far short of their objective, since they were running out of space (and air, you would think - I think they punched a “snorkel” up every so often for fresh air).
