Having worked in construction and a bit in building science, there is a single major problem with subterranean construction:
Water.
Diffusion/osmosis means that moisture is going to want to go from high to lower concentrations. Untreated poured concrete is permeable and will allow water to seep through if installed without any sort of vapor barrier. There are building products to help out here, but it’s difficult to identify leaks if you are only leaking a 0.1oz of water per day, it evaporates faster than you can identify it. Once it has some refuge (humid air, damp environment, porous surfaces) it will begin to accumulate and cause problems. I’m not saying it’s not impossible (I think under ground stuff is cool and we should have more of it), but we need to develop standard, cheap methods of reliably sealing off our structures that reach down below.
There are other problems that are site-specific (sandy soils, clays, bedrock), but building below grade happens once so these problems can be overcome with enough money.
Going below the surface has been a big thing in London for a while now, it's real estate so limited and above ground so expensive. Many of the most posh neighborhood townhouses in London have deep multi-floor underground layers.
With an environment that seems to be continually warming and becoming more hostile, going underground will probably become a natural defense that humans will take as we retreat from the harsh heat, wildfires, etc.
Yes. You have to dig, possibly using explosives to blast through rock, and install more supports, ventilation, drainage, etc. In many places you need a lot of concrete to support the structure too. You might think you're getting walls almost for free, but that doesn't happen often.
Having worked in construction and a bit in building science, there is a single major problem with subterranean construction:
Water.
Diffusion/osmosis means that moisture is going to want to go from high to lower concentrations. Untreated poured concrete is permeable and will allow water to seep through if installed without any sort of vapor barrier. There are building products to help out here, but it’s difficult to identify leaks if you are only leaking a 0.1oz of water per day, it evaporates faster than you can identify it. Once it has some refuge (humid air, damp environment, porous surfaces) it will begin to accumulate and cause problems. I’m not saying it’s not impossible (I think under ground stuff is cool and we should have more of it), but we need to develop standard, cheap methods of reliably sealing off our structures that reach down below.
There are other problems that are site-specific (sandy soils, clays, bedrock), but building below grade happens once so these problems can be overcome with enough money.
The Machine Stops by E.M.Forster (1909):
https://en.wikipedia.org/wiki/The_Machine_Stops
[pdf] https://web.cs.ucdavis.edu/~rogaway/classes/188/materials/th...
Going below the surface has been a big thing in London for a while now, it's real estate so limited and above ground so expensive. Many of the most posh neighborhood townhouses in London have deep multi-floor underground layers.
With an environment that seems to be continually warming and becoming more hostile, going underground will probably become a natural defense that humans will take as we retreat from the harsh heat, wildfires, etc.
Isn't London at risk of floods with climate change and sea level rise? Not sure that is the best place to invest in underground structures.
Related: https://www.wired.com/story/london-underground-flooding/
https://archive.is/8cEHA
thank you
And past: https://en.wikipedia.org/wiki/Derinkuyu_underground_city
Isn't it expensive to build underground?
Yes. You have to dig, possibly using explosives to blast through rock, and install more supports, ventilation, drainage, etc. In many places you need a lot of concrete to support the structure too. You might think you're getting walls almost for free, but that doesn't happen often.
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