Elon Musk's 5 keys to breaking through with a tunnel boring machine
When Elon Musk announced on Twitter he was starting a new venture called The Boring Company to solve traffic woes, most wondered how serious he really was. By way of slick animations, TED appearances and chatter on social media, the tech tycoon is starting to show that he isn't messing around. The Boring Company, as it is known, has now updated its website to reveal yet further detail on Musk's vision for sprawling underground tunnel networks, including a section that clearly lays out the key technological challenges ahead.
"To solve the problem of soul-destroying traffic, roads must go 3D, which means either flying cars or tunnels," the website reads. "Unlike flying cars, tunnels are weatherproof, out of sight and won't fall on your head. A large network of road tunnels many levels deep would fix congestion in any city, no matter how large it grew (just keep adding levels)."
In an onstage talk at TED in Vancouver last month, Musk explained that to make this project work the team would need to cut the costs of tunnelling by a factor of more than 10, while also speeding things up. Shrinking the size of the tunnel is one way to do this, so rather than a typical 28-foot wide tunnel (8.5 m) for a one-lane road, the team will burrow 14-foot (4.25-m) tunnels and shuttle cars along electric sleds. This should apparently reduce tunnelling costs by three or four times.
But there is still a big need for speed. Musk jokes that snails move 14 times faster that current tunnel boring machines (TBMs), and has now set out to beat a pet snail called Gary in a race. The Boring Company's FAQ section lays out the five ways it hopes to achieve this. Musk did touch on these in his TED discussion, but here they are in black and white.
Increasing TBM power output is first, which it says can be tripled while fitted out with suitably scaled-up cooling systems. Then there is an ability to continuously tunnel. Current approaches will spend half the time digging and half the time building support structures for the tunnel. The Boring Company believes it can do both with modifications to existing technologies.
Third is automating the TBM so that it can run entirely on its own, without the need for human operators to improve efficiency (and safety). Fourth is a move to all-electric machines, replacing the diesel-powered locomotives that power some current devices, and finally, investment in tunnelling R&D, which it says is currently non-existent in the US.
One interesting takeaway on this final point is that The Boring Company will start investigating technologies that can turn the excavated dirt into bricks to construct tunnel structures. This would negate the need to cart the soil off for disposal, which costs money and time, and reduce the reliance on concrete, which is a sizeable contributor to greenhouse gas emissions.
This could all be seen as a serious simplification of the complexities involved in tunnelling. For example, only soft soils are mentioned, whereas any tunnelling endeavors are likely to involve all manner of Earthy muck. There is sand that can damage the machinery, along with other matter like rocks, gravel and clay.
The largest TBM ever built, named Bertha, recently tunnelled beneath Seattle where it had to contend with eight different types of soil. The soil was actually so radically diverse, something caused by glaciers during the last ice age, that it even varied across the 57-ft (17.4-m) face of the cutting machine.
One other significant problem the The Boring Company will contend with is water, a major factor in tunnelling missions. Water in the soil ahead makes it easier to shift and bore through, but too much and the machine will effectively be trying to cut through mud, where it is difficult to make much progress at all.
In any case, Musk's business blueprint certainly lends itself to slipping past incumbents in fields where there appears to be little or no innovation happening. And though he said last month that "this is basically interns and people doing it part time," the current job listings on The Boring Company's website seem to suggest otherwise. Among the 10 openings are roles for a Certified Crane Operator for 110-ton Crawler Crane, TBM Operator, TBM Segment Installer, Tunnel Design Engineer and a "California Professional Geologist and Certified Engineering Geologist."
The team has also begun digging at SpaceX headquarters near Los Angeles, where its TBM, called Godot, is making its first moves against Gary the snail. The race won't be fast won, but will be worth keeping an eye on all the same.
Source: The Boring Company