Constructing an underground cave

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SUMMARY

The discussion centers on the theoretical construction of an underground cave using a series of five resonators, specifically tuning fork drills, to create vibrations that would fracture the surrounding rock. The proposed method involves synchronizing the vibrations of the rods along different axes to maximize the tearing effects on the rock. However, several participants argue that the complexity of this method is unnecessary and suggest that a sonic drill would be a more practical solution for the character's needs, especially considering the narrative focus on Alzheimer's. The consensus leans towards simplifying the construction process to maintain reader engagement.

PREREQUISITES
  • Understanding of vibrational mechanics and resonance
  • Familiarity with sonic drilling technology
  • Basic knowledge of geological properties of rock
  • Concept of material pliability and its effects on construction
NEXT STEPS
  • Research the principles of vibrational mechanics in construction
  • Explore the functionality and applications of sonic drills
  • Study geological engineering techniques for rock fracturing
  • Investigate the effects of temperature on rock pliability
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Writers, particularly in the science fiction genre, who are interested in realistic construction methods, as well as engineers and geologists looking to understand the implications of vibrational techniques in rock excavation.

SIQI
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Hello, I'm currently working on writing a story. This one involves a character that lives pretty much by himself and he has a built underground cave.

Unfortunately I do not have the tools nor dexterity to test it out myself, but in theory it should work, just asking around to see what people think of the construction method.

suppose you stick a series of 5 resonators (i.e. tuning fork drills, any rod base that can be set into a particular vibrational frequency along an axis.)
If you would have them all plunged into fitting holes on 1 axis of which we will call the X-axis (Say This is North to South).
Now the rods 1, 3, and 5 are sent into vibration in such a way that it is vibrating along the Y-axis (this would be West/East). Though on the same resonant frequency they are 90 out of phase with each other as in when rods 1 and 5 are as max swing to the east, rod 3 would be at max swing to the west. This vibration sets up divides along the Y-axis between the rod much like Earthquakes would be caused when tectonic plates slide across the other.
Rods 2 and 4 are added in between rods 1 and 3 & 3 and 5 for better focus on a weakpoint in the geometry of the ground rock. Rods 2 and 4 are sent into vibration instead on the Axis 90 deg out of phase with each other (so when one is thrown North, the other is thrown South). And they are synced up in such a way that when they are at maximums so are rods 1, 3, and 5, supplementing the tearing effects made by those rods.

This is just 1 line of rods; to create the sides for something like a square shape we'd have more in parallel sent into vibration thru maybe sound and then into resonance across the array maybe thru wire connection of the right length between like poles.

To make this work, the guy also makes sure to create a minor resistance differentiation between the region he is working on to that of the surroundings before starting work. What is meant here is that he is making the surroundings more pliable by a fraction so that there is somewhere for the stress caused by the vibration to resolve within his control. This can be done using several methods of heating/cooling the main way I can think of is using the sun's natural energy and covering up the square he will be working on during the day while concentrating the heat on the surroundings and during the night trapping in the heat on the surroundings while letting the square he works on be left open to stay cool. (Liquid may or may not be used for this part I don't think I going that much into detail). Over the course of a day or 2 worth of preparation in changing the pliability of the surrounding by just a fraction while the temperature differentiation is still in the clear, it should be enough to work with so that the fissuring of the rock layer happens to occur just up to that edge of difference (because is then boarder of least resistance).

What I based my thoughts upon:
The breaking of a material is basically trying to move apart the way atoms are interlocked, this is the only real difference between the conjoined piece of concrete of which we can grab as 1 whole to one that is smashed into bits by a hammer.

Vibrating things vibrate on a specific axis in the direction to which they are set off on vibration. This can be seen in stringed instruments and such when plucked. So we should be able to set the rods vibrating in the directions we want them to be.
Now I am aware of the synchronization of metronomes but all videos I've seen on those have the system basically coupled together by magnetism or something else like setting them on soda cans, but that won't be the case here so I think the rods should be able to vibrate out of phase.

Pliability:
I was taking this into account because just like how you can't continuously enlarge a hole without removing the rock bits, you can't create a fissure without the side atoms having to either remain further compressed or displaced into an area of lesser pressure. The best mental picture I can draw out for this right now is perhaps liken to a rocking horse (vibrating system) in a crate with the crate being representative of the boundaries of the hole that you are trying to create, else you can have structural weakening and increase risk of collapse when the cave space is further expanded down. Now at same temperatures it is like having that crate filled with hardened concrete and the horse sent into vibration, you can crack the concrete for sure, but you'll probably damage your crate (like you can see with concrete filled backyards that ends up damaging the house edges/walls as well when small quakes happen due to the whole setup being made so rigid and inflexible compared to having just plain old loose soil). What heating the surroundings prior to work does would be to make it more "liquid-like", the rock is obviously still solid but the internal motion gained to heat is going to make a slight more more liquid like so if a vibration is passed thru it, it can offset it in multiple ways along planes orthogonal to the vibration rather than acting like a more solidified whole and tilting the whole area in large chunks along with the epicenter.
In other words I suppose its like creating an small scale earthquake on the XY plane with its impact being confined to an area by displacing the energy along the Z axis at the range of where the impact is to be confined.

The concept of this for the start of the construction of the cave my character has should work right? Though it's mainly a story about how he manages his life with alzheimers, I do want to get other details in as soundly as I can. Perhaps the pliability factor would be negligible and perhaps you can get by with 2-4 rods per line rather than 5 but I'm just mainly looking to see what you guys think about the methodology in it.
 
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No, I don't think it would work the way you've explained it here. However, I also don't think it's even necessary to go into that much detail. If you want your character to dig out a cave using a sonic drill, just give him a sonic drill and have him go to work! The details of how the drill works are mostly unimportant. And there's enough variance in yet-to-be-developed technology to let you tailor things in a way that you want.

SIQI said:
What heating the surroundings prior to work does would be to make it more "liquid-like", the rock is obviously still solid but the internal motion gained to heat is going to make a slight more more liquid like so if a vibration is passed thru it, it can offset it in multiple ways along planes orthogonal to the vibration rather than acting like a more solidified whole and tilting the whole area in large chunks along with the epicenter.

Unless you're heating the rock by upwards of a thousand degrees or more it isn't likely to make a difference. The boundary is more likely to be set by natural irregularities or weak points in the rock than by anything your character could do (without using some sort of futuristic technology of course).
 
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Drakkith said:
No, I don't think it would work the way you've explained it here. However, I also don't think it's even necessary to go into that much detail. If you want your character to dig out a cave using a sonic drill, just give him a sonic drill and have him go to work! The details of how the drill works are mostly unimportant. And there's enough variance in yet-to-be-developed technology to let you tailor things in a way that you want.
That's why I like sci-fi writing. Anybody can do anything without having to worry about how exactly it works. Of course, I detest when people add made up words.

OP should stick with the character just using a sonic drill. Unless it's a textbook, not many readers are worried about how the drill works.
 
SIQI said:
Though it's mainly a story about how he manages his life with alzheimers... I'm just mainly looking to see what you guys think about the methodology in it.
Sorry, but I think this method would be worse than the MC directly banging his head on the rocks. At least, alzheimer (something like that) would sure to follow. Just think about what air hammers do, and how that feels.

I agree with the others before me. Just give him a drill and make him work before he forgets what's this all about (or your readers puts down the book).
 
This video might help.
 
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