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The Evolution of Tunnel Boring Machines

construction-physics.com

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Re: The Evolution of Tunnel Boring Machines

#101

Post by j-a-a-p »

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…

> Today? Most of my generation struggles to make rent because we're being bled dry.

As a kid I remember visiting a friend who lived in an old workers house. I was in awe to see such a small house, and in shock to learn they actually bought two houses and connected them.

Re: The Evolution of Tunnel Boring Machines

#102

Post by drewmol »

Animats wrote: post #62
foota wrote: post #56

Earlier quoted context omitted.

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?

Either each car needs a driver or you need something to keep all the trailers precisely lined up. One new system has that; a human drives the "locomotive" and the trailers have automated steering to follow the lead vehicle precisely enough to not bump into traffic in the other direction. This is still experimental. At the other end of the line, outside the tunnel, there's a whole rail yard. The different kinds of car…

tired vehicles

Re: The Evolution of Tunnel Boring Machines

#103

Post by j-a-a-p »

karaterobot wrote: post #42
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…

That 25% statistic is unreferenced (or else I'd have to read all the sources to find where he got that from). It's sort of difficult to imagine it being true. Because you'd also have to factor in all the people who got decompression sickness but didn't die of it, but who couldn't work anymore—you'd think that would be even higher. I have to believe that it's to be interpreted as "of the many workers who died during t…

My grandfather was for a short time in the railroad construction business under Japanese leadership about 50 years after the Hudson project. I have never met him, but I can imagine he would be delighted if the death rate would just be 25%.

IIRC for the Indonesian, voluntary workers the death rate was 80%. For the prisoners like my grandfather the rate was lower, simply because they started working later (and perhaps some racism from the leadership).

Re: The Evolution of Tunnel Boring Machines

#104

Post by _8j50 »

krisoft wrote: post #91
_8j50 wrote: post #80

Earlier quoted context omitted.

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 bas…

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

Rivers from the lakes to unpopulated arid or drought striken parts of the country.

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

To use it to create a fresh water source that will feed a river. The evaporation I perhaps wrongly assumed will become rain somewhere relatively near by? But even without that, my assumption is most arid places were green at some point, re-introducing water will green them up and make them habitable for humans and generate economic activity. Salton sea in california, as disastrous as it is for example, you will see a lot of farms next to it in the middle of the desert!

> 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?

Minus the last cleanup part (except for debris). Our "waste" (not trash but toilet waste), can fertilize soil but also st high enough desalination volumes we wouldn't need to recycle water. But to meet the aforementioned need of artificial fresh water generation, we can use our waste. In cities we are already doing this except it mostly just feeds into the ocean or a bigger existing natural river, instead of that, we fill up waste lakes that drain into artificial rivers and now that water and nutrient helps grow plants, farms,etc...

If we make it work, everybody wins. More green, cooler planet, better economy, more housing along artificial river paths, transport,etc...(my original idea was actually to create these rivers next to interstate highways and gradually build high speed rail as well.

Much of the US is empty and unpopulated because there is no fresh water supply or doil that can sustain crops of any kind and we have growing national and planetary crises that might be alleviated by this including jobs,housing, climate, wars over resources,etc...

Re: The Evolution of Tunnel Boring Machines

#105

Post by TeMPOraL »

Animats wrote: post #62
foota wrote: post #56

Earlier quoted context omitted.

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?

Either each car needs a driver or you need something to keep all the trailers precisely lined up. One new system has that; a human drives the "locomotive" and the trailers have automated steering to follow the lead vehicle precisely enough to not bump into traffic in the other direction. This is still experimental. At the other end of the line, outside the tunnel, there's a whole rail yard. The different kinds of car…

> Either each car needs a driver or you need something to keep all the trailers precisely lined up.

A perhaps very stupid question, but why not make the cars self-driving the way we built self-driving robots from LEGO as kids? That is, line-following cars. It's effectively a virtual track - but I imagine painting a line or building it from cheap plastic would be cheaper than putting actual rail tracks in, and unlike generic driving automation, line-following is an old, well-understood and solved problem.

Re: The Evolution of Tunnel Boring Machines

#106

Post by bluGill »

rob74 wrote: post #90
andbberger wrote: post #65

Earlier quoted context omitted.

car travel would be a lot less appealing in throughput if subject to the same stringent separation requirements as rail travel.

The stringent separation requirements are because of the long braking distances of trains, cars have much shorter braking distances - however even those are routinely violated by drivers. In Germany, the rule of thumb is "half your speed", i.e. 25 m for 50 km/h, 50 m for 100 km/h etc.

The US used to use a rule of thumb like that, but counting seconds is a lot easier than estimating distances.

Re: The Evolution of Tunnel Boring Machines

#107

Post by s1artibartfast »

benj111 wrote: post #93
s1artibartfast wrote: post #77

Earlier quoted context omitted.

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?

You failed to quote the critical part of the sentence.

>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.

People were less obese, spent less time battling disease, and died younger.

It's somewhat similar to survivorship bias, but it is a real effect.

You can look up population incidence and prevelance rates for diabetes, obesity, alzheimer's, and cancer yourself.

Re: The Evolution of Tunnel Boring Machines

#108

Post by s1artibartfast »

dredmorbius wrote: post #84
s1artibartfast wrote: post #76

Earlier quoted context omitted.

It seems plausible to me and the Panama canal is a good comparison. 30,000 workers dies building the canal, which was 40% of the workforce. It is a lot easier to replace a few dozen men digging tunnels in New York, than find 30,000 replacements in a swamp and jungle. Life was simply cheap. If you go back 75 years further, you had pretty similar documented death rates for sailors - especially in the slave trade where…

Deaths during construction of the Panama Canal were overwhelmingly from tropical diseases, notably yellow fever and malaria: https://en.wikipedia.org/wiki/Health_measures_during_the_con... > The transmission of yellow fever by mosquitos was established by Maj. Walter Reed, US Army, the physician for whom Walter Reed Hospital is named: https://en.wikipedia.org/wiki/Walter_Reed > The shear lethality of tropical disease…

I think this further supports the point about the unfathomable cheapness of life before the 1900's.

Re: The Evolution of Tunnel Boring Machines

#109

Post by jtriangle »

pjc50 wrote: post #96
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?

Couple prototypes from what I gather. No contamination because it's a sealed system, and they're flowing molten salt through the working end to melt the rock in front of the machine as it pushes through.

Re: The Evolution of Tunnel Boring Machines

#110

Post by runarberg »

s1artibartfast wrote: post #108
dredmorbius wrote: post #84

Earlier quoted context omitted.

Deaths during construction of the Panama Canal were overwhelmingly from tropical diseases, notably yellow fever and malaria: https://en.wikipedia.org/wiki/Health_measures_during_the_con... > The transmission of yellow fever by mosquitos was established by Maj. Walter Reed, US Army, the physician for whom Walter Reed Hospital is named: https://en.wikipedia.org/wiki/Walter_Reed > The shear lethality of tropical disease…

I think this further supports the point about the unfathomable cheapness of life before the 1900's.

I would put that date a little closer in time actually. And I actually have a precise date. I think that labor was unfathomably cheap until July 6th 1935, when the National Labor Relation act was enacted.

Both the tunnel and the canal (under USA supervision) didn’t start construction until 1904.

But that said, by far the majority of the deaths during the construction of the Panama Canal were under French supervision, in the 1880s. This effort failed primarily because of the heavy toll on human lives. While people did die under the Americans, and while labor conditions were horrendous, it was nowhere near on the same caliber as the decades prior. Further indicating that you cannot just disregard human lives completely and still get the job done (you could only do that to an extend; until July 6th 1935 that is).

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