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Thermal degredation

Any experience with geothermal vertical bore holes causing heaving of asphalt parking lot?


  • Zman
    Zman Member Posts: 7,542
    What climate?
    I could see the top of the well being resistant to frost heaving and the surrounding lot moving seasonally.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    JUGHNE Member Posts: 11,021
    Was the parking lot a new install after boring or patchwork to do the drilling?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    edited April 2018
    Frost heave or bentonite (grouting) heave?

    What kind of temperatures are you seeing from the VBH loopfield?

    Also, the PE tubing does have significant coefficients of expansion...
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Jamie Hall
    Jamie Hall Member Posts: 22,916
    Don't know about geothermal wells -- but for either water supply or environmental monitoring wells, if the well is to terminate at or above the surface in any paving, the well casing itself must be isolated from the pavement with an outer sleeve, not fixed to the casing. And, of course, any drop pipe inside the casing is isolated from the casing -- vertical restraint at the pitless adapter (if used -- or from the casing itself, but only at the top) and horizontal restraint (centring or anti-torque spiders) as required but no other vertical restraint.

    I have found that over time, at least in a climate with frost or freezing, if you don't do that the paving will jack itself up the casing. Most annoying.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GroundUp
    GroundUp Member Posts: 1,865
    If the lot was paved shortly after the wells were bored and you are in heavy soil, I can definitely see it. I'm in very heavy clay here, and any recent excavation of clay in the surrounding area that is backfilled with the excavated clay is a terrible heaving mess.
  • Gordy
    Gordy Member Posts: 9,546
    First you have to determine if the well heaved, or did the parking lot settle. As @Jamie Hall pointed out hopefully there was isolation.