The shape of prime base

[tsofian]

The the little base I proposed, and some of the others being talked about the recently I think a series of rings, with different functions in the rings will suffice. each ring is 1600 feet in diameter, as that is the turning radius of a Tunnel Boring Machine.

For some manned bases, particularly Prime Base this will lead to far too much separation. Even if a tram system is used having such distances between sides of a level can eat up a lot of time.

The towers in the original module are unworkable as designed. They are fixed to the living rock and would be placed under far too much stress to survive. I am beginning to wonder if towers are not the way to go though, or some other sort of vertical structures. Elevators are much easier to engineer and operate than trains or trams.

[dragoon500ly]

And therein is the problem.

But, perhaps, a combination of towers and tunnels might do the trick. If we use the tunnel boring machines to carve out two of these rings, to be used for stores of raw material/finished goods. Then connecting tunnels with bays that will contain the various labs and production facilities and storage vaults and connecting in a central chamber, housing the command center and it's supporting functions, the living, recreation and training facilities, etc.. Then it may be possible to build blocks housing these facilities. It would even possible set aside one of two of the connecting tunnels for additional living quarters, hospital and possibly a school.

[tsofian]

I'm chewing on this. I do see towers and tunnels (are there trolls as well)

[dragoon500ly]

Tried some sketches to see how it looked.

First problem is the number of personnel assigned. How many singles Married Will there be space for teams in transit Dependents

How many months of supplies will be needed What type of production facilities

Aviation support Transport support How about naval

How many beds in the hospital What scale of care Medical labs Morgue

Space for a gym, classrooms, firing ranges

Lots and lots of concerns!

[mmartin798]

The the little base I proposed, and some of the others being talked about the recently I think a series of rings, with different functions in the rings will suffice. each ring is 1600 feet in diameter, as that is the turning radius of a Tunnel Boring Machine.

I am just wondering where you got your 1600 foot turning radius. I have seem specs on Robbins TBMs and they can turn much tighter than that. One that I have read the report on has a 4.62m (15ft) boring diameter has a 105m (344') turning radius. A similar CTS TBM that has a 4.58m (15ft) tunnel diameter has a turning radius of 61m (200ft). Even if the turning radius grow faster than the diameter of the tunnel, I have a hard time envisioning the turning radius being 5 time greater when the tunnel diameter is just doubled.

[mmartin798]

I think I answered my own question. I found a patent application for improving the calculations for turning radius of TBMs. It seems it is dependent upon the desired tunneling speed, the cutting pressure, and the strength of the material being bored. So I guess 1600' tunnel diameter could be as correct as any other number.

[tsofian]

I was looking at a 26 foot bore.

[dragoon500ly]

I was looking at a 26 foot bore.

For the regular use tunnels, workable. for a storage tunnel, and just thinking of the fun of maneuvering a 20-foot long cargo container in and out, you are more likely looking at a pair of tunnels drilled side-by-side for say a 50-foot diameter

[tsofian]

That would be a huge tunnel. Plus 26 feet wide would be plenty wide enough for moving tractor trailers and loads

[dragoon500ly]

That would be a huge tunnel. Plus 26 feet wide would be plenty wide enough for moving tractor trailers and loads

True...don't know about doing a 20' container and its tractor in a 26' wide tunnel, certainly would be something to watch! But a lot of it depends on what system of storage do you use 20'ft containers have the advantage of bulk storage and being able to be stocked several high. Pallets are smaller, easier to move around, but can't be stacked more than 3-4 high (depends on the pallet). Or you can go with shelf storage, these can be several courses high, but would require wide aisles to allow the lift platforms to maneuver.

Thoughts

[mmartin798]

That would be a huge tunnel. Plus 26 feet wide would be plenty wide enough for moving tractor trailers and loads

I am not so sure. While I haven't found any reports or guidelines for turning radius of a 20' trailer and have not worked the formulas, there are plenty for 45' trailers. For a semi to do a 180deg turnaround requires a straight road about 91' wide. If this were a tunnel, the 91' would be where the front outside corner of the truck was just brushing against the wall. If this scales close to linear, then you still need about 40' wide straight tunnel, more if it is a circular tunnel. It is possible to use specialized mules that are close in size to the hitch to minimize the turning and turn the prime movers with no trailer. This will reduce the efficiency but may do the job. But if you just want to hook up the trailer and go, a double wide tunnel is in order.

[Desert Mariner]

I may be oversimplifying things but if the tunnel is circular, would you really need to 180 the rig or would you just drive around the circle and save a lot of tunneling

[mmartin798]

You could. It's about one mile underground, but you could go the long way around if it were all open. But since this is also a base, if there are any buildings in there for infrastructure or other purpose, then you have those bottle necks to consider.

[Desert Mariner]

You could try to go the way of Norwegan's and add periodic roundabouts to the tunnel. This also provides points for branch tunnels if desired.

https://youtu.be/87K7gX9rVIE

[nuke11]

Moving a TBM around is a big deal and draws attention. What cover story could be used to mask the movement and then disposal of the spoils from the tunneling operation