Quote from: Stan-1967 on 01/26/2017 07:34 pm Alternately, he has grown to hate I-405 from his home in Bel Air driving south to SpaceX/Hawthorne. That stretch of lovely LA freeway can drive anyone insane.Helicopter
Alternately, he has grown to hate I-405 from his home in Bel Air driving south to SpaceX/Hawthorne. That stretch of lovely LA freeway can drive anyone insane.
Well one method of using heat to tunnel rock is called spalling. They use in granite quarries to cut vertical channels so they can then use wire cutting to remove slabs. Basically a oxygen fuel torch that pops off little chips from thermal expansion. It doesn't have to melt the rock. It only has to heat and crack.
I vote for a electric car only tunnel. And only electric cars with autopilot.
Elon Musk (@elonmusk); January 28, 2017 @ 11:53 pmAnd we start digging the tunnel tonight
Elon today (29th Jan) spoke at Hyperloop----------------He said the digging started today and that they were experimenting to bore tunnels at a rate of 500 to 1000 times faster than any previous boring methods.
Quote from: lambecolin on 01/30/2017 01:02 amElon today (29th Jan) spoke at Hyperloop----------------He said the digging started today and that they were experimenting to bore tunnels at a rate of 500 to 1000 times faster than any previous boring methods.I think he mean to say "bore tunnels at a rate of 500 to 1000% faster"
And my mind immediately jumps to "rocket engines" Seriously, think of how fast a rocket engine dumps out heat (spall potential). Or how much aggregate you could blast per second at high speeds into a wall, kicked up by the exhaust stream. I have no clue if this is what he's thinking, but if he's looking to channel large amounts of energy in a short period of time....
You know, new ideas often come from taking concepts from other fields that one has worked in into a totally different field. So my my mind immediately jumps to, "What concept might one bring from electric cars or rocketry to the concept of tunnelling?"And my mind immediately jumps to "rocket engines" Seriously, think of how fast a rocket engine dumps out heat (spall potential). Or how much aggregate you could blast per second at high speeds into a wall, kicked up by the exhaust stream. I have no clue if this is what he's thinking, but if he's looking to channel large amounts of energy in a short period of time....It may also leave a melt crust, too. Doubt that'd be strong enough to avoid the need for concrete reinforcement, but couldn't hurt...
Quote from: Rei on 01/30/2017 12:14 amYou know, new ideas often come from taking concepts from other fields that one has worked in into a totally different field. So my my mind immediately jumps to, "What concept might one bring from electric cars or rocketry to the concept of tunnelling?"And my mind immediately jumps to "rocket engines" Seriously, think of how fast a rocket engine dumps out heat (spall potential). Or how much aggregate you could blast per second at high speeds into a wall, kicked up by the exhaust stream. I have no clue if this is what he's thinking, but if he's looking to channel large amounts of energy in a short period of time....It may also leave a melt crust, too. Doubt that'd be strong enough to avoid the need for concrete reinforcement, but couldn't hurt...You are reminding me of something I've read close to 20 years ago (in an issue of the technology magazin P.M.). Engineers developed a new way of digging tunnels up to 10 times faster than regular, by using a rocket engine instead of the drillhead. Of course, back then that was just ridiculous, since rocket engines were expensive and could last only a few minutes.But nowadays with a company that can produce a lot of them and which can sustain several hours of work?I have no clue what this would do with the surrounding stone, or where the exhaust fumes will go, but maybe Musk is shooting for that concept.
The rock-melting drill was invented at Los Alamos Scientific Laboratoryin 1960. Electrically heated, laboratory-scale drills were subsequently shown topenetrate igneous rocks at usefully high rates, with moderate power comsumptions.The development of compact nuclear reactors and of heat pipes nowmakes possible the extension of this technology to much larger meltingpenetrators, potentially capable of producing holes up to several meters indiameter and several tens of kilometers long or deep.Development of a rapid, versatile, economical method of boring large,long shafts and tunnels offers solutions to many of man’s most urgent ecological,scientific, raw-materials, and energy-supply problems. A melting methodappears to be the most promising and flexible means of producing such holes.It is relatively insensitive to the composition, hardness, structure, and temperatureof the rock, and offers the possibilities of producing self-supporting,glass-lined holes in almost any formation and (using a technique called lithofracturing)of eliminating the debris-removal problem by forcing molten rockinto cracks created in the bore wall.Large rock-melting penetrators, called Electric Subterrenes or NuclearSubterrenes according to the energy source used, are discussed in this report,together with problems anticipated in their development. It is concluded thatthis development is within the grasp of present technology.
The excessive melted stone positioned in a ring gap produced by the melting drilling equipment is pressed in the surrounding stone. During continuous progress of the melting drilling the drilled hole is covered by a alyer of a solidified and in previous melted stone. The melting drilling equipment which receives its melting energy from liq hydrogen and oxygen discharges the energy necessary for melting the stone by one or more detonating gas flames in part of the melting head. By discharging the detonating gas flames directly against the melted stone a working temp of 3000 deg.C is achieved. This temp cannot be reached by an indirect melting method because the corrosion of the fire resistant material of the melting head would be too great.