[HN Gopher] A swarm of robots built this tunnel [video]
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A swarm of robots built this tunnel [video]
Author : cjg
Score : 42 points
Date : 2022-12-21 10:33 UTC (12 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| Gravityloss wrote:
| The content about the new method starts roughly here:
| https://youtu.be/bfJY0syocfU?t=227
| interroboink wrote:
| The Wadsworth constant strikes again (:
| nathan_phoenix wrote:
| Seems like a cool concept but also quite early stage with unsure
| viability. Curious how transportation would change if they
| succeed in making tunnels x2 cheaper.
| euroderf wrote:
| That still leaves American tunnels ridiculously more expensive
| than elsewhere in the West. There are more reliable wins
| elsewhere in the overall process.
| geocrasher wrote:
| Seems very "Popular Science" to me. I expect to see that when I
| see the Moller Sky Car in production.
| strangattractor wrote:
| Looks much more interesting than the Boring Company. They look
| large enough to fit something other than Tesla's through them.
| throwawaymaths wrote:
| This is 100% how the first permanent (i.e. not tin cans) lunar
| habitation will be built, possibly Mars too.
| bagels wrote:
| What gives you such confidence in your statement?
| dylan604 wrote:
| using a throwaway account gives one all sorts of confidence.
| melling wrote:
| @6m Could build tunnels up to 10 times faster and at half the
| cost.
|
| A lot of US cities could be retrofitted with subways.
|
| Even NYC metro area badly needs a few more tunnels:
|
| https://en.m.wikipedia.org/wiki/Gateway_Program_(Northeast_C...
| hutzlibu wrote:
| "Could build tunnels up to 10 times faster and at half the
| cost."
|
| Maybe. So far they have only drilled through wood and not
| stone.
| sroussey wrote:
| While this method can create new tunnels, I see it's first best
| use at enlarging existing tunnels by setting the "concrete" type
| stuff surrounding an existing tunnel but at a larger diameter
| (well, also need not be round!). Then demolition of the existing
| tunnel walls and some cave in of other materials and you have a
| new larger tunnel after cleanup.
| dylan604 wrote:
| You'd still lose use of the existing tunnel. Why not build a
| new second tunnel?
| Animats wrote:
| Now that's an interesting idea. Dig a ring of small holes around
| the perimeter of the tunnel and use them to build the tunnel
| liner. Then remove the dirt and rock in the middle.
|
| Microtunneling has been around for years. It's done with small
| tunnel boring machines, to install pipes of various sizes.[1] The
| drives are usually not that long, because these are pushed from
| the starting point, not self-propelled like the big TBMs.
|
| That's what they seem to be doing here. There's some hand-waving
| around the "special borepipes". Those are apparently drilled by
| existing techniques. Only when all those tubes are in place
| around the perimeter of the tunnel volume do the robots move in
| and grout. Trying to do all that pumped concrete grouting work
| with those small tubular robot vehicles is a neat trick. The
| animations show them drilling small crosswise holes longer than
| the tube diameter, which is a bit suspicious.
|
| All this would seem to be limited by how far you can drive the
| "special borepipes" using standard drilling techniques. That can
| be quite a distance, though; the current microtunneling record is
| 2.2 km.[2] That's more than enough for most urban projects.
| You're going to want stations and access points along the route,
| so the drive can be done in sections.
|
| (When watching the original post video, start at 3:30 to skip a
| long ad.)
|
| [1] https://www.youtube.com/watch?v=teVrJs6CSe0
|
| [2] https://www.napipelines.com/building-big-microtunneling-
| terr...
| amelius wrote:
| What is the advantage? You have to remove the dirt in the
| middle either way. And with a bigger drill you can get through
| tougher obstacles.
| afinlayson wrote:
| I figured the Boring company had a similar approach, but when I
| researched their technique ... I was very disappointed. This is
| really cool. Can't wait to see it go into production.
| thombat wrote:
| How does Boring's technique differ to conventional current
| approaches? (i.e. I'm too lazy to repeat your research..)
| tshadley wrote:
| So the robots are building the shell of the tunnel before the
| material within the tunnel (spoil) is removed.
|
| The robots do not seem specifically involved with removing spoil
| or even carving it into smaller pieces (at least pieces smaller
| than the tunnel diameter).
|
| Does this mean building tunnel shells is the hardest part of
| tunnel building, not breaking up and removing spoil?
|
| Or does this approach somehow make it easier to fragment and
| remove the spoil since it's now in tunnel-sized chunks?
|
| (Edit: Yes, stabilising the tunnel is the hard part, see
| excellent and thorough answer by rmccue)
| rmccue wrote:
| Stabilising the tunnel is the hard part; anyone can dig a hole,
| but keeping that hole stable is what makes it a tunnel. The big
| innovation from Brunel and the ancestor of most modern tunnels
| was the tunneling shield [1], which provided an area to safely
| work ahead of the supporting structure.
|
| Modern Tunnel Boring Machines (TBMs) incorporate a tunneling
| shield, with the addition of a large machine behind the cutting
| head which builds the tunnel walls as it goes along.
|
| The innovation here is to build the stabilisation first and
| tunnel out the rest; it seems more akin to pipe/box jacking [2]
| in that sense, where you basically force the outer walls
| through the material using hydraulics, then excavate the spoil.
| Their demonstrations so far are at the scale where box jacking
| would probably make more sense, but if they can deliver on the
| promise of having effectively an arbitrary long tunnel then
| that'd make the technique more broadly applicable.
|
| [1]: https://en.wikipedia.org/wiki/Tunnelling_shield [2]:
| https://en.wikipedia.org/wiki/Pipe_ramming
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