I’m joining the EV club

As I requested, let us please leave Elon and the Boring Company out of this discussion. They have no track record in this area and all promises are not even close to fruition. If a project like this is to be done, you have to have both great engineering and project management capabilities and there are only a few firms in the world with those skills and the Boring Company is not one of them. Every such project other than possibly in China, have had massive cost overruns, the Boston Big Dig being another example. (China is not a good example as they have an abundant supply of cheap labor who can be conscripted or be put in prision, no environmental impact analysis, no law suits, material that can be procured at below market prices etc. Even with that the Hong Kong Macau bridge is supposed to cost $20 billion )

 

Bechtel can do it...

 

Bechtel would differently be one of them and Flor possibly. There are a 2-4 in Europe including Vinci. SNC_Lavlin in Canada may be able to do it. Some of the biggest companies with this experience are Chinese. I am not sure how they would fare when there is a lot transparency and they cannot bully employees and suppliers.

 

I think Vinci sucks, having worked with them on a couple local jobs here in Seattle, they are overconfident, and really struggled with our challenging geological features, Vinci is still being sued over the last tunnel project they did in Seattle.

Bechtel did the new Hong Kong Airport which was a massive job.

 

You have no right to make such a request. Gooki is the one who created this discussion thread, and it was he who brought up the possibility of a Boring Co. tunnel between the two New Zealand islands. If anybody has the right to set rules for discussion in this thread, it's him.

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I am sorry but I do not agree with you. Any poster can make a reasonable request if the discussion is veering of track. Any discussion on Elon just generates a lot of noise and frankly unproductive discussion. This a discussion began with the OP buying a car, and went into transportation between the north and south islands and then morphed into what a "$@#" Elon is. There are enough threads about Elon and his crimes or the lack thereof, and I can always request that another thread not wander into that topic.

 

The Boring Company has yet to complete a tunnel with all the safety systems for humans to travel through, EGRESS paths, fire sprinklers, communications, railings, etc. The boring company just bored a sewer hole and lined it with concrete liners, that's the cheap part. And they did it in near perfect soil conditions, when boring under the water table you have to put compressed air ahead of the TBM shield to keep the water from flooding your new tunnel, this sounds simple, its not... Also the deeper you go underground the higher the required pressure. Seattle's Bertha tunnel machine went 250 feet below sea level right next to Eliot bay, there was some serious hydraulic pressure on that tunnel project, not to mention political pressure.

On a typical subway project about half the cost is the rolling stock (trains) so when you see the price that seems so high, you have to remember what is included, the second most expensive part is the stations, and the tunnels themselves are the cheapest part of the system. They also typically drill subway tunnels 20+ feet in diameter, to allow space for track bed, safety equipment and systems, and EGRESS pathway in the case that a train stops underground. Typically subway trains on high volume routes are spaced just 2-3 minutes apart, which in a place like Taipei is 2500 people every 2-3 minutes at peak on one direction line, don't forget each line has 2 tracks, one in each direction. High speed rails tend to space out the trains further as it takes longer to stop at 200 MPH+, without sending the passengers flying. High speed trains do use regen braking, but the difference is the energy is generated and used in A/C so you do not need a giant inverter to convert all that regen energy to put it into a battery. On a typical HSR rail system they add energy to the system at several locations, and usually have trains on the system slowing while others are accelerating to share the energy. The control and coordination on a typical HSR system is impressive, they keep those trains on time to the second typically. Unfortunately in the USA we do not have any of these systems because the government is too short sighted to see the environmental benefits.

 

Just remember that the Cook Strait has both complex/irregular terrains and dangerous currents. The average depth is 420 feet, so it is deeper than the English Channel. From Wikipedia (https://en.wikipedia.org/wiki/Cook_Strait )

The strait often experiences rough water and heavy swells from strong winds, especially from the south. New Zealand's position directly athwart the roaring forties means that the strait funnels westerly winds and deflects them into northerlies. As a result, ferry sailings are often disrupted and Cook Strait is regarded as one of the most dangerous and unpredictable waters in the world.

Also in addition to storms, there are earthquakes
2013: Two large earthquakes measuring 6.5 and 6.6 on the Richter Scale struck Cook Strait, causing significant damage in the town of Seddon, with minor to moderate damage in Wellington.

No wonder that the ferry ride takes 3 hours. This means any construction (undersea tunnel, oversea bridge) will have frequent interruptions due to weather, need extra precautions and have to deal with more safety concerns, which will all push up the price significantly. The technology exists, but not at an affordable price. (This is where program management comes in to manage risks, and this is where the company, whoever it is, has to show great skills in, if there is a ever a plan to build it.) It appears to me there are good reasons why this idea has not taken off. Here is an 2018 article, which discusses this idea.


https://www.stuff.co.nz/the-press/news/101061154/is-it-time-for-a-cook-strait-bridge-or-tunnel

Is it time for a Cook Strait bridge or tunnel?

The Cook Strait is a violent body of water. It's an exception. Unlike other straits around the world, it has opposite tidal flows at either end. When it's high-tide on the Tasman side, it's roughly low-tide on the Pacific side and vice versa

Before the end of the last Ice Age, you might have been able to walk between the two islands – if there had been anyone around to do it. But for the last 20,000 years this strait has divided New Zealand in a way most countries have never known.

What if the country could become physically connected again? Is a Cook Strait bridge or tunnel pure fantasy?


ROBERT KITCHIN/STUFF
What if the country could become physically connected again? Is a Cook Strait bridge or tunnel pure fantasy? Julian Lee investigated.


There would be far more to gain than just the novelty of being able to take a 27 hour 2,000 kilometre drive from Cape Reinga to Bluff: an immense increase in traffic between the two islands, the untold billions saved in shipping and flying costs, the Marlborough and Wellington areas thriving and booming from increased commerce, the tourist dollars, the sheer convenience of replacing a three-hour ferry ride (and its associated on- and off-loading times) with a short drive.

It's an idea that's so outrageous even some of our more seasoned politicians have never heard it being raised before..................

Ask someone in the know and they will quickly explain that it is a pipe dream...........

The article proposes other alternatives, but lays out the challenges and the fact that it is not going to be cheap by any means.

 

Yes, I was thinking that driving your car onto a Chunnel train car and sitting and waiting until the next run probably isn't much different than driving your car onto a cross-channel ferry and sitting and waiting until the next run. Well, not much different as far as logistics go. The view during the trip is rather different.

 

That is a real problem. Many critters would be more than happy to wander across a bridge or through a tunnel and not all are benign.

Bob Wilson

 

Let us face it, even in an very environmentally conscious country like New Zealand, if there was an economic argument, then there would be people clamoring for it, without considering environmental impacts Clearly, based on my limited research, there is no real impetus or groundswell of support for such a physical connection. This is due to the construction challenges including those of the topography, the occurrence of frequent storms/inclement weather, the possibility of earthquakes and the uniqueness of the currents and flows. This directly translates into higher costs, especially if have some environmental additions The estimates I see are minimum in the $25-20 Billion, may be higher, which is almost the cost of the Chunnel, which handles about 10 times currents volumes. Even with an increased usage, it still be about 30% of chunnel volumes. So, again, I have known to be wrong, but I do not see any serious consideration

 

Early congratulations. Good luck with your new car. How long will it take?

 

Maybe it's a lack of imagination on my part, but I can't see why rough seas would delay a tunnel construction project. They're not going to be working in the water, after all. I suppose that might delay shipments of building materials and the like to the project, but since that's a known factor, it should be possible to account for that in planning and cost estimations. Contrariwise, I completely agree with a point you made in an earlier post, "interestedinEV", where you said that such projects experience cost overruns frequently, and it seems likely (I would say almost certain) that would happen here.

Seems to me the interruptions of ferry service due to rough seas would be an economic incentive in favor of the project. Rough seas wouldn't affect tunnel traffic! But if they have to go extra deep, that plus the rather modest amount of traffic that a traffic tunnel would serve, would indeed seem to make the project too costly for serious consideration.

I'm not at all sure the danger of earthquake is a real concern. Elon Musk said, regarding his Boring Co. proposals for traffic tunnels in California, that a tunnel is actually the safest place to be in an earthquake. Now, perhaps it's unwise to take him at his word on that, but I presume he knows rather more about the subject than I do.

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Good thing I didn't just take a swig of my coffee after reading that...LOL.
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In order to do the drilling underwater, I am going to assume that there has to be on the surface support who cannot work if the weather is very bad. Also, there has to crews at each end who have to help and may not be able to do so in bad weather. How much ever you plan for it, there are always the unknowns. I did not say it cannot be done, my point was that it will cause delays and cost escalations, some which could be planned for. Having managed complex projects, what you have to do then is to add a bunch of contingencies, for the "unknowns". Back to money and time.

Also I do no the answer to this, but if you were having a major storm on the surface, would you continue operations under the sea, knowing fully well that if there is an emergency or if something goes wrong, that you will not be able to get any support from land or surface based resources?

The cook channel is deeper than Chunnel. So any tunnel will have to go deeper. The more I read about it, I think I understand why there are no serious considerations to actually build this tunnel or bridge. The technology does exist even today, the costs are expected to be prohibitive.

I am not a structural engineer and I am going to pass on if Elon is qualified to make such statements. Here is an academic article on the subject which suggests that the design may have to adjusted to make tunnels more resilient to earth quakes, which again adds to cost and possibly, time. The author acknowledge that moderate earthquakes may need no modification to design. However, a few years ago there was 6.5 to 6.6 magnitude earthquake which is considered strong. There is no guarantee that the next one will not be more intense. Also a very important, in this article, the author says, tunnels in rock are more resistant. I have not been able to find an article that tunnels under the sea are more resistant to earthquakes. The Elon quote did not mention under the sea. I do not know if this statement also applies to undersea tunnels.


https://www.sciencedirect.com/science/article/pii/S2467967417300053

The tunnel industry has considered that tunnels, especially tunnels in rock, are naturally resistant to earthquake action, including faulting, shaking, deflection and ground failure. As the number of case histories of tunnels subject to earthquake action has increased, the industry has started to recognize that, although tunnels in rock have good resistance against earthquakes generating peak ground accelerations (PGA) lower than 0.5 g, it is important to include the dynamic forces and displacements generated by seismic ground motions in the design process to obtain a more reliable design. These additional earthquake forces impact the final design, potentially requiring changes to the ground support and additional reinforcement of the concrete lining, as illustrated by case histories presented in this paper.

 

I'm not sure what you mean here. Once the bore holes are well started, working from both ends toward the undersea middle, any working crew would be able to get in out of the weather, and I can't see any need at all for working on ships on the surface of the ocean. I suppose especially bad weather may make it difficult to run the trucks or whatever they use to carry debris out of the tunnel, but mere rough seas shouldn't stop or slow the tunneling at all, unless they run out of supplies and have to wait for more to be shipped in via sea.

As has been noted in previous comments here, there won't be any ventilation shafts coming down from the surface, because the "surface" would be under the sea! All ventilation will have to be supplied by bringing air in from the ends, which I presume is the setup with the Britain/France Chunnel.

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I have to respectfully point that while you feel that weather will not have any effect on drilling a tunnel between the north and south islands of New Zealand but you have not provided any other corroboration.

Again this is not my area of expertise, so while to me weather appears to be a consideration, and that the may cause the project managers to slow down construction activities if there is going to be very bad weather on the surface. However I do acknowledge that I do not know enough to tell you that you are wrong and I am right or vice versa. Neither do I have any evidence one way or the other. So I could be completely wrong.

However, the discussion on smaller points like this takes away from my bigger point which are that there many "unknown unknowns" and that constructing a tunnel or a bridge between north and south islands of New Zealand is both going to be very costly and risky, no matter what the method, based on current construction techniques. I understand this hypothetical but I do not see such an tunnel idea taking off, at least in the near future.

Also, I just found this article that points that there are different methods of building underwater tunnels including newer techniques that might make a difference. If they used the cut and cover method for example, I would expect a lot of surface activities. (Again I have no idea if cut and cover can be used here. TBMs were used for the Chunel but today there may be other choices.)


https://www.wonderopolis.org/wonder/how-do-you-build-a-tunnel-underwater

Another new method of creating underwater tunnels is the cut-and-cover method. To use this method, builders dig a trench in the riverbed or ocean floor. They then sink pre-made steel or concrete tubes in the trench. After the tubes are covered with a thick layer of rock, workers connect the sections of tubes and pump out any remaining water.

This method was used to create the Ted Williams Tunnel, which connects the southern part of Boston with Logan Airport. The 12 giant steel tubes that were sunk in the trench were each 325 feet long and already contained fully-constructed roads!

Engineers are always coming up with new ideas. Based upon experimental rock-cutting methods, tomorrow's underwater tunnels might be built with the help of high-pressure water jets, lasers or ultrasonic sound machines.

New technologies could enable the building of tunnels that once seemed impossible.