Brilliant and well done, Joe. Curiosity satisfied! I appreciate your comprehensive explanation of how these Boring Co. TBMs have evolved, developed and operate. More, more! Thanks for all your work on documenting and informing us. Bravo!
Following your comments that this may be the only use of Prufrock 3. It may have been decided that, due to the delay in the Tunnelling works, it will not be removed in its main component parts. The extension structure is being completed along the path that looked like it had been left for the TBM removal. Plan B could use the ever more common method of removing all the back up decks back along the tunnel, right up to just leaving the cutterhead, bearing, bulkheads and shield skin behind. These are then butchered (lot of use of the gas axe) into handleable sections and scrapped. I have managed a number of projects where this and variations on the idea have been utilized.
Very interesting. Confirms much of my understanding of what TBC are doing. Remote (surface) control room is a good development for TBM's of this size. Keeps some people out of the tunnel, although the 4 man operation team seems a bit OTT in comparison to most TBM's (1 possibly 2 people). Japanese contractors were experimenting with this some decades ago, largely driven by a shortage of experienced operators. Several TBM's operations could be managed from a central control room at the head office, possibly hundreds of miles from the site. Similarly, a Herrenknecht AVN machine is a closed loop excavation, non man entry TBM, with all operations from the surface, and can be continuous mining (except the installation of the next pipe), these Pipekack TBM's are limited to about 4.1m diameter at present but another 150mm to get to the TBC diameter must be possible. The issue is the transport and size of the pipes. It begs the question why not just buy one of these machines? A 3.2m diameter one is operating a few km from me as we speak, launched from the surface, halfway up a hillside on a very small worksite. I don't accept the porpoising approach claim that a smaller site is required. See the size of the site at Giga Texas, and the amount of land the TBM took up to exit the ground next to the golf course in your video. I have managed larger TBMs that had the whole operation working from a site the size of a basketball court, and an exit shaft in a site less than 6m x 6m, in some cases no exit shaft at all. Site constraints in dense urban environments often lead to some of the most imaginative technological solutions. So Prufrock 3 is already heading for retirement, a far cry from the claims regarding its potential performance when it was "unveiled" last year. Lets see what versions 4 and 5 bring. Thanks for all the effort Joe. Despite my cynicism, its great to see tunnel construction being discusses among a wider audience and your drone videos have been the backbone of this debate. Please keep it up.
Maybe version 3 is internally already judged in the Rapid Fail category, to continue Joe's analogy, with the next versions coming out all that stronger. If I could ask a question on the rapid iteration analogy that is used: a rocket is tested in order of magnitude minutes, but testing a tunnel may take order of magnitude years because of its required longevity. Is that why you mentioned earlier that climbing the technology curve for a new entrant in the tunnel boring business takes so many years? In any case I admire the attitude of trying to build the future, go get-'em! And I hope that top notch players such as Herrenknecht will take it in their stride: Bring It On! Whatever, us watchers are in for a treat, where will it emerge and when? Also I hope that some of their testing will involve making curves, if only to make our guessing game more interesting. Unfortunately you have already explained very clearly the First Principles involved in arranging the concrete sections in a ring (Not Rocket Science now that I know the trick!..).. but perhaps tighter curves is on their to-do-list.
@@hardernl8893 All good points. I do believe the analogies to Space X are in some ways limited as the whole risk/reward process for building robust infrastructure compared to space exploration are quite different. I doesn't necessarily take years. Teratech are a successful smaller independent TBM manufacturer that hit the ground running, without billionaire backing, and are growing in the market, with similar size/type of TBM's to TBC. I also admire anyone for trying. Indeed, the large plant company Caterpillar tried entering the TBM market some years ago through the purchase of the Canadian Lovat company, it didn't succeed, when one would think they had a real chance of hitting ground running so to speak. I credit anyone who is willing to invest in developments for the future, but TBC need to get a bit more realistic in their aims if they want to be seen as credible players in the market. Tighter curves have been done with very specialized machines, but they don't really work with the conveyor system, or rapid excavation. 125m radius is a realistic minimum. TBC are already doing a vertical curve in this tunnel, (about 900-1200m radius) even though it is straight in plan. Many years ago I was the Engineer on an "S" curved pipejack tunnel, even though most Engineers would tell you they can only be built in straight lines.
As others mention, the tunnel exit point inside the building extension is most interesting - and we may not even get to see that happen, given the rate of extension construction as girders and floors and roofs join the main building. Looking down with the drone cameras, it is difficult to judge space sizes. Precision tunneling navigation is certainly required to avoid the building foundations and other existing underground structures, pipes, conduits, etc., as the tunnel exits. Very shortly, the two cranes inside will be carefully backing out themselves. TBM seems even bigger than the cranes. How and at what point in construction that will be extracted (using SPMTs supporting a jig?) seems unclear, although I'm sure all that is thoroughly planned. But Part 1 & 2 videos have sure helped to understand the process. Thank you, Joe.
We should get a view in for some weeks at least. Once the TBM reaches the perimeter grade beam and stops for removal, or continues on a little further we should still get to see inside until the perimeter grade beam and retaining wall is completed, then the windows installed.
@@DessieDoolan Sure hope so. I (for one) am really looking forward to the tunnel exit. I have just assumed that the tunneling machinery would continue forward to be extracted from the tunnel and removed. But maybe the whole thing is designed to "back out?"
@@WarrenLacefield As mentioned elsewhere by David Salisbury, the back-up decks/gantries can be removed back through the tunnel if required. Although not if the road deck is installed. The TBM itself being larger than the finished tunnel can only be removed from the tunnel end.
Thanks Joe for the very informative video and explanation of the Boring Company Tour Part 2. I would like to know more HOW porposing down and up is accomplished.
Did anyone notice Joes small graphic at 2:02 showing TWO tunnels crossing under the highway. He never mentioned it in the video but 1st time seeing that maybe there will be more than 1 tunnel at that specific location!😊
Joe, looks like you compared the Boring Co tunnel to railway tunnelling which is done on a far larger scale. The bored section of a railway route is generally a small part as the diameter is based on the minimum needed for the whole route. To save boring, the open part of the railway route is done by cutting, and the railway TBM sits in the cut. Railway TBMs also use a converyor to move earth from the TBM and they use rubber-tyred vehicles to bring segments into the tunnel.
@@JoeTegtmeyer Interesting how much the application influences the TBM. Elon keen to automate a system that could be used on the Moon and Mars. Obviously, TBM for railways on Earth won't go go to the moon. Boring Co service could be described as luxury public transport. In the next couple of years we could see it as an automated service.
Its a "Universal ring". The ring they are using is nominally 60" long. But it is 59" at one side and 61" at the other. To visualize this, imagine you slice a salami, but angle your knife slightly left then right with each slice. Now rotate every second slice by 180 degrees. Voila! you can go round a corner. By rotating each progressive slice to any one of 16 available positions (16 dowel connections round the ring) you can go in any direction, up, down, left, right or straight. By doing this the segmental rings can follow the path the TBM excavates.
Awwww, the most important question is how far have they tunnelled and when will they finish this first tunnel, also when will they start the next tunnel and will they join all tunnels together, so many questions and none of them should be that hard to answer. Joe you have access nobody else has and really should be asking the questions we are all eager to know.
@@davidsalisbury50 I'm curious: considering how long it took to set up, wouldn't it be better for them to just go on tunneling all the way to the parking garage, rather than having to set up on the other side for that second tunnel?
@@greggerypeccary Minimum radius for this TBM would be about 125m, and that is without considering the conveyor alignment. Not sure how this could be achieved among the foundations of the main factory building. Also the tunnel needs to come to the surface at the extension for the new vehicle delivery.
Did I miss the part where you showed where the tunnel would end? Did you mention how fast the process was going or how far they had tunneled so far? Good PR for the Boring Co, anyway.
Maximum 10m per day, average around 6m, currently about 165m into what is expected to be a 300-320m tunnel. All a bit of educated guesswork based on what we have seen in Joes videos over the last 4 months.
great information Joe, thank you. I wonder if the TBM has a GPS to indicate how far they have tunneled. This could be shared on their website page for those interested.
If they are up to date with their guidance system they will be using a combination of lasers, a gyro theodolite (It knows where north is), and traditional surveying techniques to back that up. If not, then a total station theodolite and laser optical system is the simpler method.
@@robertthallium6883 I'm talking about guidance, steering the tunnel, not just how far they have gone. Lasers are used to predict where they are going not just where they have been. They should know to the nearest mm where they are in x,y, and z coordinates.
Best explanation I have seen of Boring Company process. You left Gidot and Line-Storm out of your timeline. Is there enough ability to take up slack to use a common size tunnel segment, or are the segments customized to go around a corner. Also, it is normal to inject some sort of grout between the tunnel and the surrounding soil. This part of process was not mentioned, or maybe not done?
Great videos (as usual) On a lighter note, your photos of Prufrock 2 at around the 20 minute mark sort of remind me of the Graboids from the movie series Tremors, the way they porpoise through the ground lol
just need use a spiral design of tunnel sections. Seem simple, if your not pushing off this section, could premould like screw/bolting..allowing a pushing place. back 1 row ..plus(required if non stop) of tunnel.?? would constrain interior space..leaving difficult maintainer/repair space yes auto matic be best
Per Joe, its likely inside the new south building extension. Once cars come off the line they can jut be driven (or hopefully drive themselves) thru the tunnel and over to the processing and transpo lot.
@@tnelly6588 thats what I was thinking too, only thing is how are they going to get the prufrock out now since its looking fully enclosed, looks like it would be a really tricky situation
@@sybo10There are several options with other tunnelling techniques. One is to leave the machine in place. Simply tunnel a bit further, and seal off the tunnel end. Then you can tunnel beyond the active tunnel, dig down from the surface, and lift the equipment out. Or steer the tunnelling head out to the surface. If they are going to be making multiple tunnels, there could be multiple methods used. The excavation on the East side between the South extension and the cooling tower structure might be for removal of the tunnelling hardware.
Surprised to see that the 'bolting' of liner segments is still not automated. This means that humans are currently right behind the boring segment. Pretty sure they'll solve it very soon so there are no humans inside the tunnel during the boring process
Chinese have solved robotic erection of linings. So have the Germans and the Japanese in trial systems. However, it does require much larger tunnels than TBC are building. A lot of the most advanced tunnelling tech will not work in such a small tunnel. If you go a little smaller you can use non man entry pipejacking (AVN) techniques. Also, by using dowels on the circle joint and locator bars (already cast into the TBC concrete moulds but they don't seem to be using them) tunnel linings up to 6m diameter can be erected without the use of any spear bolts. Did a cable tunnel using this type of lining in 2005. In many medium/large diameter metro rail tunnels the bolts are removed at the back of the TBM backup and recycled forwards for re-use. The finished tunnel has no bolts.
Hi Joe you mentioned zero people in future making the tunnels underground do you foresee the same staffing levels being cut for the production of EV’s with the advance in FSD will the EV’s when at the end of the production line drive themselves away from the end of line through the boring tunnels to the fast chargers automatically connecting to the chargers then when enough charge added they will drive to the parking areas and wait to be called to the pre delivery building all without human intervention.
Nice. They have to have goals for speed in the design. Why wasn’t this basic parameter covered? What is an average time required per mile or range. Although the tech seems good not impressive if you don’t compare speed and cost improvements.
Two things I can't wrap my head around - how does Prufrock turn without leaving a gap in the soil from the tail swinging out of the final tunnel path? And are there special liner segments with different angles for turning? And what does TBC do about the gap around the liners? Since they appear to be installed just inside the shell of Prufrock, seems like there is a gap all the way around the outside that would eventually settle. Even a few inches all the way around I would think could eventually cause small sagging right?
See above for how the rings build to go round corners. The TBM has an articulation joint about 2-3m back from the cutterhead. This allows up to 150mm of articulation on this first section of shield. TBM's generally form an overcut at the head, sometimes have a "copy cutter" (in rock) that moves in and out slightly as the cutterhead rotates. The whole skin of the TBM is sometimes slightly tapered (10-20mm along its length) to avoid it getting trapped in squeezing ground. The segmental lining is usually 100-200mm smaller than the shield, to allow for the physical thickness of the shield skin (which must be able to withstand soil and hydrostatic pressures. this leaves a gap as it is pushed out of the tail. The gap is sealed at the back of the shield by wire brush seals which are constantly injected with a thick grease (often with fibres in it) to stop water/soil running back into the TBM down the back of the segments. as the TBM progresses and the segments exit the back of the shield an annulus is left behind. This is continuously filled with a cement grout, usually in combination with an accelerator to cause rapid hardening. this stabilizes the ring and minimizes settlement of the ground from the disturbance form the tunnel construction. Plenty of RU-vid videos to better explain it. Try the Herrenknecht website as a good starting point.
Joe - I wonder about the curved (diving then surfacing) tunnels. Do the concrete liner segments have enough slop in the joints to allow for the slight curve? Or are the concrete segments shaped slightly differently to accommodate the bend? It would seem to me they may have different forms for the concrete segments used in the curved sections. Great information Thanks.
Its a "Universal ring". The ring they are using is nominally 60" long. But it is 59" at one side and 61" at the other. To visualize this, imagine you slice a salami, but angle your knife slightly left then right with each slice. Now rotate every second slice by 180 degrees. Voila! you can go round a corner. By rotating each progressive slice to any one of 16 available positions (16 dowel connections round the ring) you can go in any direction, up, down, left, right or straight. By doing this the segmental rings can follow the path the TBM excavates.
@@davidsalisbury50 Thanks for explanation, I was wondering this and couldn't find the answer in joe's video. I was like all those pieces are the same or what? It make sens now :)
I wonder if they could eliminate all the conveyor and gantry system by modifying the tunnel segment truck to bring in the segments and then carry out the spoils.
Most EPB TBM's operate with the spoil in muckcars, These a re generally on rails and cant accommodate steep inclines such as TBC's porpoising approach. The gantries are still required as they carry all the backup systems for the TBM, a shorter conveyor runs across them and discharges into the muckskips at the back of the TBM. Watch the Herrenknecht videos for better animated explanation.
@@natpainter8185 Nah!, Just early vapourware by TBC and Mr Musk. Tunnel segmental lining requires very high specification concrete, using high quality control materials.
Wow, great video! Incredibly well produced, Joe! Definitely seems that Tesla is often so obsessed with iterating, that they can become their own worst enemy. The DBE process for the 4680 batts is a perfect example. The cost to constantly be changing the mass-scale production equipment has to be astronomical.
@tnelly6588 It doesn't always work. In fact, at some point it always fails. But if you never try something new, you'll never improve. Remember how Starship was supposed to be Carbon Fibre? Then all that was thrown out? Now look at Boeing's Starliner. How is that doing? How about FSD? V11 to V12 was starting from scratch, but the improvement in the last 6-12 months has been phenomenal. Sunk Cost Fallacy.
FRAU MARLISA AHL SA BERLIN NAA KOY EGSOON DIHA SA TEXAS BABAYE GA MINYO SIYA COSTOM SA TEXAS DUGAY NA SIYA GAPUYO SA US ANG TRABAHO AKUNG EGSOON DIHA NAA KAHA
