Overflow Drilling
Overflow Drilling
(OP)
We have a problem of leakage for two holes, how to stop the water outflowing?
After 10 meters of weak peat we met the clay layer that contains an important aquifer located down to it. The clay layer did burst while drilling and let the waterflow outgoing from casing with 8 cum/h discharge and 1 bar pressure at floor level and leaking in surrounding soil.
Nowadays water is still running as it was not possible to grout the hole in spite of pumping water. Because of running water that get the grout out and sprays it in surrounding soil. No grouting pressure can be used due to peat.
If anyone faced similar case or has got any idea to solve the problem, please let me know.
After 10 meters of weak peat we met the clay layer that contains an important aquifer located down to it. The clay layer did burst while drilling and let the waterflow outgoing from casing with 8 cum/h discharge and 1 bar pressure at floor level and leaking in surrounding soil.
Nowadays water is still running as it was not possible to grout the hole in spite of pumping water. Because of running water that get the grout out and sprays it in surrounding soil. No grouting pressure can be used due to peat.
If anyone faced similar case or has got any idea to solve the problem, please let me know.





RE: Overflow Drilling
Could you seal the hole by pouring in bentonite grout mix ? The mix can be made as a thick grout, or mixed with sand and cement so that it will be heavier than water (tends to go down the hole, rather than floats). You may have to inject the grout at depths (by using a grout pump into the hole), hence replacing the column of water above it, and creating a column of heavier liquid than water (therefore can stay and not expelled out of the hole).
Bentonite is critical in the mixture, as it swells or expands, and therefore will inhibit water flow. It may need time, and waste of the bentonite-cement mix, but the flow will slow down as the bentonite swells.
If flow is small, you may just use bentonite pellets and drop them in the hole. The pellets come in different sizes, from pea size, marble size to powder. You can even mix bentonite powder with water and make your own "bentonite balls" to the required size (1 to 2 in. diameter), and drop them one by one into the hole. Bentonite alone is heavier than water, so it may go down. You have to do it slowly to ensure that the hole is not plugged too quickly. To ensure a long term seal, you have to create a good column of bentonite seal, say at least 30 cm, and then backfill the remaining hole with cement grout or soil).
Hope that this helps
RE: Overflow Drilling
If this height is too excessive, try putting an inflatable borehole packer into the caly layer. Use one that allows you to pump grout through it. Seal the hole below the packer and get your packer back, if possible.
RE: Overflow Drilling
RE: Overflow Drilling
25 gal water
3 bags portland cement
3 to 4 100 lb bags of barite
The mix will be very heavy and a temporary casing should be set to the bottom of the peat.
A high volume will have to be pumped at first to overcome the water flow. Afterward the grout will have to be watched for settlement and kept topped off.
RE: Overflow Drilling
RE: Overflow Drilling
The truth will set you free. Best of luck. Geodude