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Freezing of subsoil is frequently performed during construction projects, for instance when building new underground tunnels in London. It sounds awfully expens
by smilespray 5y ago
Freezing of subsoil is frequently performed during construction projects, for instance when building new underground tunnels in London. It sounds awfully expensive for a permanent installation, and raises questions about what happens if it's not maintained well or the power goes out.
- throwawayboise 5y agoBut it might be feasible to do it to solidify the soil as they drill through it to the bedrock.
- smilespray 5y agoSure. Freezing is usually done to stabilize neighbouring structures. Extending the piles down to bedrock level was quoted at $500m, so they ditched the idea for this project.
- ethagknight 5y agoMaybe they freeze the low side to allow the differential settlement to balance back out. I don’t think freezing is that challenging or expensive (on the scale of costs they are having to consider here) and would take weeks to thaw out. Also, the freezing need not be super deep or expansive, just at along original foundation pile to give them more “grab” in poor conditions. Freezing could be used as part of a perm fix too. I bet there’s a way to sequentially freeze subsoils in such a way to use frost heave to actually push the building back into original position to augment the foundation. Or create a frozen layer in the mid-foundation and then pump in high pressure concrete grout below the frozen layer. Freezing water is a powerful thing… Armchair civil engineering is fun