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The Evolution of Tunnel Boring Machines

construction-physics.com

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Re: The Evolution of Tunnel Boring Machines

#91

Post by krisoft »

_8j50 wrote: post #80
lstodd wrote: post #59

Earlier quoted context omitted.

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.

There are lakes such as superior in michigan or even mammoth lakes in cali. I also wondered why not instead of recycling desalinated water after use, have it fill up a lake. Use nuclear powered (dedicated power plant) desalination to fill up artificial lakes. People talk about colonizing mars but if we can't even do this on earth then how is that more practical?

> There are lakes such as superior in michigan or even mammoth lakes in cali.

Yes. Lakes as a concept exist. There are many examples. What are you proposing?

> I also wondered why not instead of recycling desalinated water after use, have it fill up a lake.

Okay. Just for the aesthetic value? Or to evaporate it?

Let me get it straight: you are proposing to pipe the output of wastewater treatment plants to an open basin (also known as artificial lake). Ones whose waste input was generated by humans drinking desalinated water. So your proposal is to desal, consume water, turn it into waste, clean waste, fill lake. Do I understand you well?

And you are asking “why not”. Let me turn it around: why exactly?

> People talk about colonizing mars but if we can't even do this on earth then how is that more practical?

It is not.

Re: The Evolution of Tunnel Boring Machines

#92

Post by benj111 »

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…

We've got richer while food has got relatively cheaper, transport has got relatively cheaper, all the things you need to live have got relatively cheaper, so it isn't really surprising that all the extra money is going towards people's homes.

On top of that all the nice things have gotten cheaper. Listening to music is now cheap. Books, news, entertainment are cheap.

Yes you may have had a car (24 million cars in 1940 v 135million population) but then you wouldn't have had a fridge, TV.

And youre comparing someone relatively wealthy, to someone who can't afford rent. If you were poor you probably didn't have electricity, indoor toilet, more than one heated room in the house, and probably lucky if you could afford enough food.

I'm from the UK and we went through this a bit later so it's still within living memory. My dad remembers getting an indoor toilet an plumbed in bath for the first time, that was late 50s/ early 60s.

Re: The Evolution of Tunnel Boring Machines

#93

Post by benj111 »

s1artibartfast wrote: post #77
mschuster91 wrote: post #53

Earlier quoted context omitted.

> 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…

And if we are talking late 1800's/early 1900's, Taxes were essentially non-existent, so people kept and spent more of their money. Taxes as a % of GDP was in the 5-10% range, opposed to ~40% today. They also didn't have to worry about the same healthcare costs, as they were healthier in general, and the options were far fewer when sick.

>as they were healthier in general

Source? Survivorship bias?

How many people do you know who've had polio? Small pox? Rubella? Mumps? Died from a bacterial infection? Blinded from cataracts?

Re: The Evolution of Tunnel Boring Machines

#94

Post by ben_w »

rob74 wrote: post #87
ben_w wrote: post #24

Earlier quoted context omitted.

There is nothing that we can do to this planet that would render the environment a tenth as inhospitable as any known other planet. IIRC we've not even found one that has free oxygen in the atmosphere yet. Even if we did, anything with that and water would be extremely exiting by the standards of exoplanets, even if it had an average temperature of 75 C which would kill humans.

> There is nothing that we can do to this planet that would render the environment a tenth as inhospitable as any known other planet That's yet to be proven - although not in my lifetime, I hope. One would hope that humankind would finally manage to do something before it gets as bad as on Venus, but I wouldn't bet on it...

Getting as bad as Venus would require as a minimum crashing a quarter of the entire asteroid belt into planet Earth, and that's assuming there's enough oxygen and carbon in those rocks.

Even if we burned 100% of all biomass on Earth, leaving it dead, it's still not close to Venus, where the "air" is so thick it's passed the critical point and no longer distinguishable from a liquid.

Even if we did that, the day length on Venus is longer than its year.

Re: The Evolution of Tunnel Boring Machines

#95

Post by pjc50 »

ttyyzz wrote: post #14

Funnily enough, my father is at the 11th international symposium on “Ground Freezing” in London at this very moment. Most of the time you have to freeze the ground before you can drill. He has been working in specialist civil engineering for many years and builds tunnels all over the world. He has told me many exciting and hard-to-believe stories about tunnel construction and tunnel boring machines. E.g. during the w…

Burying TBMs is not uncommon. The HS2 ones are being buried for an indefinite period due to UK government flipflopping. https://www.ianvisits.co.uk/articles/hs2-will-bury-two-tunne...

There's one in New York. https://untappedcities.com/2017/02/09/the-200-ton-tunnel-bor...

Re: The Evolution of Tunnel Boring Machines

#96

Post by pjc50 »

jtriangle wrote: post #85

And no mention of nuclear tbm's, even though NTBM's were remarkably fast and fixed many of the issues with traditional tbm's...

Were any of these ever built? Googling suggests Los Alamos patented one, but I can't see examples of one being built and tried. How bad is the resulting contamination, and how do you keep it out of the groundwater?

Re: The Evolution of Tunnel Boring Machines

#97

Post by benj111 »

Gare wrote: post #31
ttyyzz wrote: post #14

Funnily enough, my father is at the 11th international symposium on “Ground Freezing” in London at this very moment. Most of the time you have to freeze the ground before you can drill. He has been working in specialist civil engineering for many years and builds tunnels all over the world. He has told me many exciting and hard-to-believe stories about tunnel construction and tunnel boring machines. E.g. during the w…

> E.g. during the work on the Eurotunnel. Here the British tunnel boring machine was diverted into the rock near half the length of the tunnel and left there. It was cheaper than somehow taking it out again. AFAIK it was not just the cost, but the problem of two TBMs (British and French) meeting head to head. The british were driven out of the way so that the French ones could proceed.

I wonder how many political meetings were had, to decide who got out of the way of who.

Or maybe it was the toss of a coin? But then a franc or a pound?

Re: The Evolution of Tunnel Boring Machines

#98

Post by [deleted] »

ggm wrote: post #35

The projection for boring company is interesting at least. They seem to argue most of the "wins" are procedural, and relate to business practices, paperwork and general business efficiency, the "we can do 1km a day" claims not withstanding (they don't claim this. But, it is definitely an out-there claim of their speed) -The reality of the equipment and process they use is still an advance on most, but it's more norma…

[deleted]

Re: The Evolution of Tunnel Boring Machines

#99

Post by j-a-a-p »

teruakohatu wrote: post #43
cyberax wrote: post #40

Earlier quoted context omitted.

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.

They did know migrant workers were dying, they thought it was a sickness caught being below ground so they kept them in dorms away from everyone else. When you are hiring new people each day, to replace the ones who died, knowing that a quarter will lose their life, ignorance around exactly how they died is no excuse. Today in my country at least a single workers death is not acceptable. Accidents happen but prosecut…

> Today in my country at least a single workers death is not acceptable

Tolerance for workers death is highly related to location and time. We used to have large families for a reason!

N=10, but nevertheless a comparison on the difference in location at exactly the same time was the Channel [0], of the 10 deaths, 8 were in Britain.

[0] https://en.wikipedia.org/wiki/Channel_Tunnel#:~:text=At%20th....

Re: The Evolution of Tunnel Boring Machines

#100

Post by BlueTemplar »

ben_w wrote: post #24
rolph wrote: post #15

Earlier quoted context omitted.

yes crops will have to be included, as well as a, cohort of supportive biotypes. very much a noahs ark scenario, but we may best use a number of avenues, such as exoplanetary colonies.

There is nothing that we can do to this planet that would render the environment a tenth as inhospitable as any known other planet. IIRC we've not even found one that has free oxygen in the atmosphere yet. Even if we did, anything with that and water would be extremely exiting by the standards of exoplanets, even if it had an average temperature of 75 C which would kill humans.

Free oxygen is not something that happens naturally, it requires a specific kind of life to constantly replenish as it gets consumed by surface oxidization.
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