Ground Freezing
As with ground de-watering this is not a new phenomenon by any means with welsh minors using this practice from as far back as 1862. Now i will admit that the following is purely anecdotal as i have never used the system myself, on the few occasions i have obtained quotes for such works the price has been prohibitive due to the size of the contract and in comparison with ground de-watering, this does not however mean that this system does not have its place.
The process involves sinking shafts by various means into the ground and then freezing the water content of the sub-soil using a coolant by either employing a large refrigeration unit or more commonly liquid nitrogen
The advantages of this system would seem to be that as you are not removing water from the sub-soil and you are reducing the vibration associated with traditional piling there is a lesser risk to surrounding structures particularly in built up areas, the ground when frozen is impermeable which is of benefit in a tidal zone and stable therefore requiring no shuttering, the process is also said to be environmentally friendly.
I look forward to being corrected on any of the points above by people in the know, particularly if it involves a site visit to see the system in operation.
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