The Evolution of Tunnel Boring Machines • Hacker News Board

Re: The Evolution of Tunnel Boring Machines

#51

Post by Animats » Wed, Oct 11, 2023, 1:19 AM UTC

Little or no mention of the back end of the machine. The front end, where cutting takes place, gets all the attention. The segment placing arm got a mention. But most of the length of the machine does other things.

The usual TBM setup has a two-track narrow gauge railroad behind it. Segment cars bring ring segments forward, and muck cars remove the spoil. Track cars bring more railroad track. Tool cars and worker cars are in the mix occasionally. All this is happening on an unfinished railroad, because the back end of the TBM has to lay the track and move cars from one track to the other. All the stuff for this takes up more length than the cutting part. A tunneling project is an entire construction site compressed into a long, narrow hole. So logistics in the tunnel are a big deal.

Now, this is where The Boring Company was expected to innovate. Something involving driverless Tesla chassis, maybe. But they never did. Others have built such systems.[1] But not The Boring Company.

[1] https://tunnelingonline.com/mobiletronics-demonstrates-auton...

Re: The Evolution of Tunnel Boring Machines

#52

Post by jauntywundrkind » Wed, Oct 11, 2023, 1:26 AM UTC

Anyone else immediately search for Subselene, the nuclear-powered thermal tunnel boring idea proposed in 1986?

I tend to think they pretty heavily underbid how much heat input it would have taken? The design review for a 3m diameter tunnel going 30/m a day was 56 MW. I am not an expert, but a couple horsepower of thermal energy seems low to melt through the moon.

https://www.osti.gov/biblio/5262838

Re: The Evolution of Tunnel Boring Machines

#53

Post by mschuster91 » Wed, Oct 11, 2023, 1:32 AM UTC

Retric wrote: post #49

culi wrote: post #41

Earlier quoted context omitted.

They were paid $2.50 a day. Which is around $91 in today dollars. On top of that wage theft was all too common. And that's a wage that they had to fight to unionize to get up to

Assuming I am reading this right in 1905 1/4 of male workers over 16 made 8$/week or less. https://babel.hathitrust.org/cgi/pt?id=nnc1.cu56779232&seq=1... For unskilled labor 6 days a week at 2.50/day = 15$/week which would have been quite tempting especially if the risks where unclear. It’s worth remembering when doing inflation calculations just how poor people used to be. Take the average person’s budget today and…

> It’s worth remembering when doing inflation calculations just how poor people used to be.

And also, how much of the wealth created by the employees ended up in their pockets vs. the pockets of the owners, and how the standards of living were. Basically, back then with such a job you could afford a place to live, to have kids, a wife to take care of housework and, post 1930-ish, a car. Today? Most of my generation struggles to make rent because we're being bled dry.

Re: The Evolution of Tunnel Boring Machines

#54

Post by soperj » Wed, Oct 11, 2023, 1:42 AM UTC

matjet wrote: post #47

alistairSH wrote: post #29

Earlier quoted context omitted.

The majority of people in the US live in urban and suburban areas. There’s plenty we can do in these areas to reduce car-dependency instead of paving more roadway (which ends up as waste of time due to induced demand).

I think you misunderstand induced demand. The increased demand when you add more capacity, simply means even more utilisation is achieved -> increased productivity. This is not a waste of time. The correct comparison should be comparing for each area and situation, which type of transport investment results in the greatest utility. The objective is not to minimise traffic, but to maximise peoples ability to get where…

No, it just makes things farther apart, and more people sit in traffic jams. That's decreased productivity.

Re: The Evolution of Tunnel Boring Machines

#55

Post by jcims » Wed, Oct 11, 2023, 1:49 AM UTC

digging wrote: post #25

jcims wrote: post #17

Sometimes when I'm stuck in construction traffic I wish someone would invent the Highway Widening Machine. A machine that in one fell swoop can grind, grade, prep, pour and paint a new lane into a road.

A common but misguided desire.

Of course, but it would be fun to design and build. And since it will obviously never happen it seems pretty harmless to think about?

Re: The Evolution of Tunnel Boring Machines

#56

Post by foota » Wed, Oct 11, 2023, 1:55 AM UTC

Animats wrote: post #51

Little or no mention of the back end of the machine. The front end, where cutting takes place, gets all the attention. The segment placing arm got a mention. But most of the length of the machine does other things. The usual TBM setup has a two-track narrow gauge railroad behind it. Segment cars bring ring segments forward, and muck cars remove the spoil. Track cars bring more railroad track. Tool cars and worker car…

Just curious, if the rails are such an issue, is it not just cheaper to drive the cars (no need for self driving?) or is paying someone to do it not worth the complexity savings? Or are there other downsides to not having the rail?

Re: The Evolution of Tunnel Boring Machines

#57

Post by cwillu » Wed, Oct 11, 2023, 2:12 AM UTC

Animats wrote: post #51

Little or no mention of the back end of the machine. The front end, where cutting takes place, gets all the attention. The segment placing arm got a mention. But most of the length of the machine does other things. The usual TBM setup has a two-track narrow gauge railroad behind it. Segment cars bring ring segments forward, and muck cars remove the spoil. Track cars bring more railroad track. Tool cars and worker car…

If the Boring Company mention was an attempt to combat the hype (“everybody is talking about yet another musk company”), you've contributed to the problem in much the same way as the saying regarding traffic: “You're not stuck in traffic, you are traffic.”

Re: The Evolution of Tunnel Boring Machines

#58

Post by kiba » Wed, Oct 11, 2023, 2:13 AM UTC

mschuster91 wrote: post #53

Retric wrote: post #49

Earlier quoted context omitted.

Assuming I am reading this right in 1905 1/4 of male workers over 16 made 8$/week or less. https://babel.hathitrust.org/cgi/pt?id=nnc1.cu56779232&seq=1... For unskilled labor 6 days a week at 2.50/day = 15$/week which would have been quite tempting especially if the risks where unclear. It’s worth remembering when doing inflation calculations just how poor people used to be. Take the average person’s budget today and…

> It’s worth remembering when doing inflation calculations just how poor people used to be. And also, how much of the wealth created by the employees ended up in their pockets vs. the pockets of the owners, and how the standards of living were. Basically, back then with such a job you could afford a place to live, to have kids, a wife to take care of housework and, post 1930-ish, a car. Today? Most of my generation s…

Lifestyle inflation, urban planning, and choices makes living a quality life more difficult than it should be.

You're able to afford a larger house and a car or two, but you're also spending more money than necessary on transportation and housing. Buying a car is expensive and so is the road built for cars. Trains are more expensive than a car, but its cost can be amortized across many riders.

Housing is a problem of both government and market dysfunction and is directly tied to our transportation woes. People are tied to the idea of real estate as an investment which means they often opposed development. Planners continued to zone only SFH, and made middle housing illegal. They also don't do mixed zoning which improve efficient utilization of land.

I supposed if income goes to workers more, they would just push the housing price higher. It can't be fixed unless we build sufficient housing.

Re: The Evolution of Tunnel Boring Machines

#59

Post by lstodd » Wed, Oct 11, 2023, 2:20 AM UTC

_8j50 wrote: post #45

Does anyone know why such machines aren't being used to create artificial rivers? It seems civilization and therefore economic activity follows where fresh water sources are. And there is already a problem in the US west with water shortage.

A river is mostly its watershed and not the waterway which while very visible doesn't matter that much. No amount of machines would help create the watershed, so no, there's no point.

Re: The Evolution of Tunnel Boring Machines

#60

Post by runarberg » Wed, Oct 11, 2023, 2:21 AM UTC

cyberax wrote: post #40

teruakohatu wrote: post #6

> During construction of the Hudson River Tunnel in 1889, 25% of the workers died from decompression sickness. Less interesting but of far greater value to humanity has been the innovation in heath and safety regulations. According to this article [1] one worker died per foot of the Hudson River Tunnel. > In 1906, attitudes toward the sandhogs changed after a series of accidents beneath the East River. Blown-out tunn…

This was not so much health and safety regulation-related, but simple ignorance. The dangers of rapid decompression were not recognized until early 20-th century when underwater construction became more common. That's why "decompression sickness" is called "caisson sickness" in several languages.

I don’t buy it. 25% of workers is a lot of workers for a megaproject of this scale. This would either have to be a single devastating week, in which case they would learn about it really quickly and would probably still be the collective memory, or O'Rourke Engineering Construction Company willfully allowed their workers to die out of mysterious causes and opted not to investigate.

The latter is actually more likely but not really. There is no way the tunnel would have been finished if a quarter of the workforce was dying and the company just allowed it to continue happening.

Compare this to the Panama Canal which started construction under US supervision the same year as the Hudson North River tunnel. They didn’t know much about the spread of tropical deceases but they knew enough to supply their workers with mosquito nets etc. The French effort to build the canal totally failed, primarily because of the high death toll among workers. When the US took over preventing the spread of deceases was a primary concern. And this project now lives in our collective memory as one that costed so many lives.

Now there is no doubt in my mind that working condition for the Hudson North River tunnel were horrendous, and that far too many unnecessary deaths resulted from total disregard of worker safety by the construction company. That this number was 25% and that it was because they didn’t know about decompression sickness... That I don’t buy, dozens of workers dying from the construction company cutting corners, overworking their workers, setting harsh deadlines, not providing safety gears, and (yes) not treating sick workers, that is far more plausible.