Best way to seal underground bore pipe which is in a pit

Question

I have a closed bore pipe whose width is 6 inches and the pipe goes upto 30 feet deep.

The bore pipe is in a pit whose depth is 6 feet.

I have other drainage pits whose water level is 1 to 2 feet from ground in normal time and 2 to 4 feet in summer time.

But this particular drainage pit whose ground is covered with gravel( broken red brick + river sand ) and which houses closed bore pipe , the water level either overflows or at the ground level.

The case is same even in summer as well.

So my theory is somehow water comes up from the sides of bore-well to the pit or the gravel reduces water pressure and hence less water filtration.

Please note all other pit has clay ground.

So what's the best way to close the bore-well once and for all. should I pour concrete or clay through the pipe or should I pull the pipe out of the ground and pour concrete or clay.I don't want water coming up from 30 feet to the ground at all.

I don't want to cause any differential settlement on the building by just pulling out the pipe and cause the ground earth to close the hole by itself.

Please leave your suggestions

Thanks

Update:

The property is located in a clay ground with high water table. I have some percolation pits on both north and south sides of property.

I'm talking with local authorities to take the water away to the nearest water canal but there's a lengthy process.

My doubt:

• Removing the gravel bed , would it help in faster draining of the water ?

• How to properly seal the underground borewell pipe so water doesn't seep through to the pit ?

Update:

Please find the pic

Answer 1

You seem to believe that this boring is encouraging flooding. This is very unlikely. It's possible that there's a more permeable lower soil layer beneath a relatively impermeable upper clay layer, where a higher water table than your local water table connects through the lower layer to your boring. You can read all about this Artesian well concept on the US Geological Survey's website if you're interested.

You can test if you've got an Artesian well by comparing the water's surface elevation to the water surface elevation in your other drainage pits. Since these drainage pits also maintain such high water surfaces, the likelihood of an Artesian well is small. I suppose it's possible that an Artesian well could raise the local water table and ultimately fill adjacent drainage pits to raise their water levels. It would be nice to have a history of when each drainage pit was dug and if the water elevation in these pits started at zero and rose in the years following the Artesian well candidate's construction. In the remote chance that you have an Artesian well, your plan to plug it with impermeable material would make sense.

In all likelihood, though, that's just a hole filling up to the elevation of your local water table. Filling it will not stop the ground in its neighborhood from being swampy. At some point in the distant future the PVC liner could fail, however, and that could impact your foundation depending on how close it is. The solution to that possible problem lurking in the distant future is to fill the pipe without removing it. Uniformly graded sand would be a good fill material because it naturally compacts fully after less than a year without any compaction equipment.