Elon Musk doesn't have the time to learn civil engineering, property development, let alone the politics surrounding it.
If Elon felt that it were necessary to get his pet project done, I believe he'd make time to master civil engineering and politics to the degree that it were necessary.
Basically, he's the real Tony Stark. ;)
More likely, he would just hire a civil engineering firm. Laws throughout the country are such that you can't really buy your way into the industry the same way he has with Tesla and SpaceX. Practicing civil engineering requires licensure everywhere in the USA.
He's just commission 2-4 TBMs (tunnel boring machines, about ~$20MM/each), drop them in the ground, and have them start digging hyperloop tunnels.
http://www.bbc.com/future/story/20150602-crossrail-the-monst...
Anyways, the cost of a TBM is generally not the most expensive part of a tunneling operation.
What is the most expensive part?
$250 million for a water tunnel that goes 3km. It's simpler than a hyper loop tunnel.
Also I'm not sure Crossrail is a good counter example. That's a 30 billion dollar project to go 73 miles. Saying the TBM cost $20 million is like quoting the cost of a truck without including the price of the driver or diesel fuel.
Part of Elon's design for the pylons allows the track to remain stable even when the pylons are moved by an earthquake. Which is kind of important with pods moving around Mach 1. Doing the same thing with a tunnel requires you to have cut a large enough hole to shift the tube inside of. Which is a massively harder piece of engineering.
As with everything, there are tradeoffs. Building above ground means land use issues, and the tunnel needs to be so small you can't stand in the hyperloop pods. Building underground means more support infrastructure, but you're limited less by politics and land use problems and more by engineering.
The questions is: which is cheaper to solve? Engineering? Or politics?
Take the 1906 earthquake as an example. As http://pubs.usgs.gov/gip/earthq3/move.html says, the horizontal slip was 21 feet at one point. Something like the Hyperloop has to be designed with the expectation of facing a similar event. Concrete is simply not strong enough to hold back a wall of dirt trying to move 21 feet.
Or for more recent history https://catalog.data.gov/dataset/landers-and-big-bear-califo... where the slip was 18 feet horizontally and 6 feet vertically. And that one demonstrates that it isn't enough to build something special for every slip zone you know about. Because in a real earthquake you are likely to discover slip zones that nobody noticed.
Why does the possibility of an offset result in a tunnel being an "emphatic no" while still allowing for this pylon idea?
Search for "earthquake" in http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf to confirm that this is a design factor the Elon explicitly considered.
How, exactly, does the pylon not suffer the same design flaw as the tunnel under the use case that you yourself brought up of a horizontal or vertical offset occuring along a splay?
If each side can move the tunnel 10 feet relative to itself without breaking, you should theoretically be able to handle up to a 20 foot slip between plates. One side bends one away, the other the other way. The pylons move 20 feet relative to each other, and only 10 feet relative to the tube.
That said, my information is based on the blueprint that Elon published and I already linked to. It includes graphs showing numerical simulations of how their design is supposed to respond to earthquakes. If you have further questions, you can start with that, then download the designs that they and others have produced and do your own work.
I am not an engineer. However I do know that engineers have done exactly what I suggested and come to the conclusion that his design is feasible.
That said, your answer is an appeal to authority. Just because a feasibility study says it is feasible does not actually make it feasible. I skimmed the document you linked and nothing in it pertains to large ground movements that would occur due to fault offset - it is all with relation to ground shaking rather than fault slip. Further, it is common knowledge, in fact, that underground structures generally perform better under ground shaking as compared to above ground structures except when the structure crosses the fault which experiences the offset. That is, tunnels work better than pylons except at the point where the large offset occurs.
I understand that you may not be an engineer. I am an engineer, with my area of expertise being in geo-structural interaction, and I am telling you that your statement about a tunnel not being feasible because of earthquakes is NOT correct. There are plenty of other reasons why a tunnel makes no sense for this job, but seismic vulnerability is not a good one. Whether his design is feasible or not is a moot point.
Secondly it is very important that the tube remain still while the pylons move relative to it. Don't forget that we have objects moving down that tube at close to the speed of sound. It doesn't take a large local kink to be a fatal problem for people inside. You really don't want that tube to move. Enough so that keeping the tube still that it is an explicit design consideration to keep it still while the pylons expand and contract for thermal reasons.
Thirdly I well know that earthquakes are generally less of problems underground than on the surface. But trading an easy problem in most places with an impossible problem at fault boundaries is hardly an improvement. That is why I have only focused on the potentially impossible problem.
Fourth, your response was just as much an appeal to authority as mine. But my appeal to authority was an appeal to authorities whose credentials are independently verifiable, whose conclusions have been put up for public comment, and which other authorities have independently questioned, criticized, and mostly verified. Your authority is based on an anonymous claim of expertise made on the internet, in a thread where you made a basic mistake about how earthquakes are measured, with no actual analysis backing it up.
Which authority is more believable?
My response is not an appeal to authority - I'm not saying "it's true because I'm an engineer". I walk you through the entire logical process, so you're free to agree or disagree with any of my arguments.
This conversation clearly isn't going anywhere so I will just reiterate my point and leave it at that: an above-grade structure will perform no better than a below-grade structure if the fault deformation occurs at the location where the fault crosses the alignment. This "potentially impossible problem" is a problem for both surface and underground structures and cannot be designed around from the structural side for the magnitude of displacement that can potentially occur in CA and, in the end, it is just a risk that has to be accepted or designed around from the systems standpoint. This is alluded to in your own linked documents and noted by the the statement:
"It is also likely that in the event of a severe earthquake, Hyperloop capsules would be remotely commanded to actuate their mechanical emergency braking systems."
I guess to answer your question: I'd probably believe me.
Have a nice day.
Make a tunnel in the ground with concrete and if the ground moves, your tunnel moves too, along with it. Unless your tunnel is stronger than the ground. Which it isn't. Or if it is, it's a 10ft diameter tunnel with 40 foot thick walls. Which is SEVERELY uneconomic.
Make it out of steel and put it in the air, and things get a lot different. The air doesn't make the tunnel move so instead of being surrounded on all sides by things which can exert force (in the ground) it's instead only acted upon by the pylons.
The pylons are supposed to be around every 100 feet. That means if the earth moves 20 feet sideways between two pylons the steel has a chance to bend and move rather than be sheared. And you can design the pylons to be strong enough to hold the tube up, but not so strong as to break the tube. So if things move a long distance, the closest pylons will break free from the tube and the tube will be supported by pylons which are further apart. That reduces the angles necessary to keep the rest of the tube on the remaining pylons which support it, and that means you're asking even less of the steel.
Sure the tube might get some bends in it that it wasn't designed for, and it might even sag down. But you can give the cars braking mechanisms that'll automatically be triggered in an earthquake so that the forces experienced when encountering these new features isn't so unpleasant.
The alternative with the concrete tube in the ground is that the tube shears into two parts which are no longer connected. That means that the tube suddenly stops and you're crashing into the dirt at 500+ mph.
Now your argument that the tube will just break free of the pylons seems like it has merit; however, the question of "why do we have all these pylons every 100 ft if we only need them every XXX ft?" should immediately spring to mind. The answer obviously lies with the rigidity of the tube between support points.
In order to get into the realm of the possibility for the steel being able to take a 20 ft offset you're talking about putting supports once a mile, at most.
Again, neither the pylon idea nor the tunnel idea have a feasible/economic engineering solution for displacement along a fault if it occurs along alignment.
Because most of the time people want to have their design include a safety factor.
Further there's a huge difference between "what this system is designed to do all day every day" and "what this system will do in the 5 minutes between an earthquake beginning and the time that the system is fully halted until repairs can be made"
Have you ever seen the remains of a power pole hanging from a power line? That would seem to indicate that there exists excess strength in the system, or that the line support structures are substantially overbuilt.
http://i2.cdn.turner.com/cnnnext/dam/assets/130601193956-15-...
I suspect that in a hyperloop you could lose 5-10 pylons in a row and what would happen is that the tube would sag well beyond normal operational parameters between the remaining pylons, quite possibly even touching the ground. The reason that so much extra strength will probably exist in the system is that there's a limit to how much deflection you can tolerate without jostling passengers too much for them to buy tickets on a regular basis. And that small deflection means that there's a lot of extra strength in the system, even though it's not strictly needed just to hold things up.
This is why machine tools have giant castings well in excess of the strength needed for the machine to stay together. It's because the Young's modulus matters far more than the yield strength or the ultimate tensile strength when you're trying to build a machine that can hold a sub 0.001" tolerance.
So if you happened to be traveling in that overbuilt tube at 500mph just after it's fallen to the ground, you'd quite likely bump (or smash) your head on the sides and ceiling of your vehicle.
But what you wouldn't do is slam into the dirt that's now at the end of the tube like you would if your buried concrete tube was sheared 20ft by a fault line.