Ground Anchors below ground water table

[Funga]

Hi!

does anybody knows how to drill a ground anchor into a soil, below the water level? I'm just talking about the unbounded lenght of the anchor, since the anchor bound will be installed in stiff clay.

Thanks in advance,

Greetings from Portugal,

Luis

 

[DRC1]

They are drilled in a similar manner dry or wet. they are either drilled with air or water and cuttings are flushed out the top. The length of the hole is cased and removed as ethe hole is grouted from the bottom up. Water table below the surface does not effect the method of installation.

 

[Doc08]

DRC1, (expanding the subject a bit) how do stop the water ffrom shooting out in case you are say 4-5m below the water table, and especially in the case of a cohesionless soil. I've read about devices available which could be fitted at the mouth of the hole to prevent water/grout/sand from escaping during drilling; however, I have not been able to locate a supplier. If you could help, I would appreciate it.

 

[DRC1]

Doc08

Generally when drilling you are looking for the cuttings to return out the hole. Drilling with water, the water is collected, desanded (somewhat) and reused for drilling. With air, which Ihave only had on a couple of projects, is messy and can shoot stuff around. I don't know whayt they use to control it, but I would expect a shroud of some sort.
Once you stop drilling, unless you are in a significant artesian condition, the water table should stablilize at its original level.

I hope somewhere in there is the answer to your question

 

[PEinc]

Case the hole to the bottom of the anchor. Tremie grout the entire drill hole. Insert the tendon (with centralizers). Pull the casing. Top off the drill hole with grout. The tendon can usually be installed either before or after pumping in the neat cement grout.

If drilling below the water table, you should flush drill cuttings from the hole with water to keep a positive water pressure head and to prevent soil from being washed up into the casing pipe. If not drilling below the water table, you can flush the drill cuttings either with air or water.

 

[BigH]

It was indicated that the anchor was to be installed in stiff clay. How much water can be squirting out into the stiff clay if below the water table?

 

[worldofmud]

I was on a job where we were drilling into an aquifer with significant artesian pressure-we used a stuffing box to prevent the rig becoming a 'water feature'-installing the instrumentation and preventing flushing out of grout was a another kettle of fish involving several diameters of casing and borehole packers/balloons....Doc008-a decent groundwater well installation contractor should no more info. regarding applications and usage.