gshp Ground Freeze

[Ally W]

I hope someone here can help. I had a GSHP installed 7 year ago and it has worked well except for the ground sinking above each of the bore holes. When they were drilling the bore hole they got to 100m  and hit water so a second bore hole of 80m had to be drilled 20m further down my drive. I always assumed the ground sinking was due to water leaking from the boreholes but now I’m not so sure. A trench 1 metre deep was dug between each bore hole and back to my garage where the GSHP is located. There are no inspection chambers above either bore hole which I thought was strange but was assured at the time was not required. 

 

This year the ground above each bore hole raised as did the ground above the trench and it is clear that it is frozen making a mess of my paved drive.

 

The question is how to a cure this and prevent a repetition. My first thoughts were come the summer to did up the drive and expose all the pipes and boreholes. Create an inspection chamber above each bore hole. Insulate all the pipes.I was also considering a duct for the connecting pipes but was worried about water ingress into that.

 

Would insulating the pipes work or would they through time just become an extension of the pipe and get as cold. 
 

Any help would be appreciated 

 

Thanks

 

Ally

 

 

 

[Marvin]

Some info:

 

https://www.sciencedirect.com/science/article/abs/pii/S2352710219330190

 

 

[Kelvin]

Did you get a drilling report for the boreholes and how they were constructed? 

[Nickfromwales]

On 20/02/2021 at 09:27, Ally W said:

I hope someone here can help. I had a GSHP installed 7 year ago and it has worked well except for the ground sinking above each of the bore holes. When they were drilling the bore hole they got to 100m  and hit water so a second bore hole of 80m had to be drilled 20m further down my drive. I always assumed the ground sinking was due to water leaking from the boreholes but now I’m not so sure. A trench 1 metre deep was dug between each bore hole and back to my garage where the GSHP is located. There are no inspection chambers above either bore hole which I thought was strange but was assured at the time was not required. 

 

This year the ground above each bore hole raised as did the ground above the trench and it is clear that it is frozen making a mess of my paved drive.

 

The question is how to a cure this and prevent a repetition. My first thoughts were come the summer to did up the drive and expose all the pipes and boreholes. Create an inspection chamber above each bore hole. Insulate all the pipes.I was also considering a duct for the connecting pipes but was worried about water ingress into that.

 

Would insulating the pipes work or would they through time just become an extension of the pipe and get as cold. 
 

Any help would be appreciated 

 

Thanks

 

Ally

 

 

 

Have you gone back to the installer?

[markocosic]

You shouldn't be freezing the ground.

 

You're pulling too much heat out for the size of the boreholes that you have.

 

Or perhaps your boreholes have hit water and the grout/ground around them has washed away leaving just a tiny bit of ground at the top for the heat pump to pull the heat from.

 

Original installer says...?