Author Topic: Elon The Boring Company  (Read 54828 times)

Offline Space Ghost 1962

  • Senior Member
  • *****
  • Posts: 2041
  • Whatcha gonna do when the Ghost zaps you?
  • Liked: 1769
  • Likes Given: 1252
Re: Elon The Boring Company
« Reply #400 on: 05/18/2017 12:25 AM »
Aw, you figured out his evil plan:


Offline sanman

  • Senior Member
  • *****
  • Posts: 3378
  • Liked: 375
  • Likes Given: 1
Re: Elon The Boring Company
« Reply #401 on: 05/18/2017 02:13 AM »
But seriously, if you could do this underground on Earth, then you could do it on the Moon, or Mars, or Titan. You have a template that can be applied elsewhere off-world.

Offline GWH

Re: Elon The Boring Company
« Reply #402 on: 05/18/2017 05:34 AM »
There was a major crossover to Mars plans in the FAQ on the boring company:
<quote> What do you do with all that dirt?
In typical tunneling projects, excavated dirt is shipped offsite to disposal locations. This process is costly, time-consuming, noisy, and can be environmentally hazardous. The Boring Company is investigating technologies that will recycle the earth into useful bricks to be used to build structures.  This is not a new concept, as buildings have been constructed from Earth for thousands of years including, according to recent evidence, the Pyramids.  These bricks can potentially be used as a portion of the tunnel lining itself, which is typically built from concrete. Since concrete production accounts for 4.5% of the world’s greenhouse gas emissions, earth bricks would reduce both environmental impact and tunneling costs. </quote>

So in addition to boring the tunnels construction materials will be created ISRU style.



Sent from my SM-G903W using Tapatalk


Offline sanman

  • Senior Member
  • *****
  • Posts: 3378
  • Liked: 375
  • Likes Given: 1
Re: Elon The Boring Company
« Reply #403 on: 05/19/2017 02:33 AM »
Does anyone know offhand how tunneling conditions would vary between the Earth, Moon and Mars?

Like say, would a lower gravity environment mean the dirt is less packed, and thus less solid? Does it mean there is less separation of heavier minerals from lighter ones? Does it mean there can be more trapped gas pockets or voids?

Could underground caverns be built much larger while requiring less reinforcement, because of reduced gravitational loads?

Online DOCinCT

Re: Elon The Boring Company
« Reply #404 on: 05/20/2017 06:45 PM »
Well, one huge unspoken issue with tunnels is the need for proper ventilation. Granted electric vehicles / sleds presents far fewer issues then combustion engines, but it's still a huge deal.

I am wondering if the motion of the vehicles in the tunnel could be used to push the air enough to ventilate the tunnel. Say at least one 'car' per minute. Also the ends of the segments would need proper design to expel air that the cars push into the station and inhale fresh air into the departing segment.
Another thought is that making the cars be encased in an aero-shell could reduce drag by 5 times or so. Of course more drag would increase the air moved.

Don't bother going underground if this is the rate.
 
Think two orders of magnitude higher (>100 cars/min per tunnel).
At 125km/hr, one car/min would have them spaced 2km apart.  At one car/sec, they'd be spaced 35m apart, so you could probably double that density (120cars/min).

At these rates, the tunnel air would be moving approximately the same speed as the cars, so just exhaust a portion and draw in make-up air.
Each tube of the NYC Lincoln Tunnel has typical traffic load of 40,000 cars per day (2 lanes wide). This works out to under 30 cars per min on average.  The tunnel uses a powered ventilation system to remove vehicle exhaust, potentially a complete change of air in under 2 mins.
Of course with an all electric system you would need less air changes.

Offline Long EZ

  • Member
  • Posts: 19
  • Oregon
  • Liked: 3
  • Likes Given: 0
Re: Elon The Boring Company
« Reply #405 on: 05/21/2017 04:47 PM »
Well, one huge unspoken issue with tunnels is the need for proper ventilation. Granted electric vehicles / sleds presents far fewer issues then combustion engines, but it's still a huge deal.

I am wondering if the motion of the vehicles in the tunnel could be used to push the air enough to ventilate the tunnel. Say at least one 'car' per minute. Also the ends of the segments would need proper design to expel air that the cars push into the station and inhale fresh air into the departing segment.
Another thought is that making the cars be encased in an aero-shell could reduce drag by 5 times or so. Of course more drag would increase the air moved.

Don't bother going underground if this is the rate.
 
Think two orders of magnitude higher (>100 cars/min per tunnel).
At 125km/hr, one car/min would have them spaced 2km apart.  At one car/sec, they'd be spaced 35m apart, so you could probably double that density (120cars/min).

At these rates, the tunnel air would be moving approximately the same speed as the cars, so just exhaust a portion and draw in make-up air.
Each tube of the NYC Lincoln Tunnel has typical traffic load of 40,000 cars per day (2 lanes wide). This works out to under 30 cars per min on average.  The tunnel uses a powered ventilation system to remove vehicle exhaust, potentially a complete change of air in under 2 mins.
Of course with an all electric system you would need less air changes.

So the moving cars will cause the air in the tunnel to move also. I would guess at least 1/4 of the speed of the cars if you had 1 car per second. This is another advantage of small tunnels; the cars being a larger fraction of the tunnel area are more effective at pushing the air along. The exchange rate of air in the tunnel then becomes a function of the spacing of the air exit/entrance vents. Other factors that would come into play are elevation changes  between the tunnel ends, and surface pressure changes (surface winds). Warmed air in the tunnels would want to rise increasing the flow rate in the direction of higher elevation and vise versa. Also consider if the LA basin Santa Ana winds were blowing 100 km/hr (60 mph) or more. That would surely create a significant pressure difference along the length of the tunnel. Tunnel air exit/entrance vents would likely have to have fans for emergency ventilation, so perhaps they would need to be used at lower rates in extreme wind conditions.
Also could the exchange rate be lower at times of low usage such as late at night as compared with rush-hour conditions? So the rate of exchange would vary as would the need for it as a function of the traffic rate.
 

Tags: