Borehole pump and pipework assembly lifting and pad design

[Andrew88]

Hi all,

Let's assume I have a borehole pump 50m below ground. The dynamic water table during drawdown is 30m beloow the ground. Now I need to lift the pump assembly together with pipework that is filled up with water. The pump is equipped with NRV valve. For the initial lifting:

- can I subtract from the total calculated weight (pipework + fluid + pump + lifting assembly) the buoyancy force across 20m submerged depth?
- if yes to above, would I only consider volume of the pipe itself so really just a shaft as I imagine the pump would still allow flow into the tube so can't treat it as a whole cylinder?

As for the pad design, I need to make it pretty thick due to the punching shear. Would you put any reinforcement in a large cube of concrete, for the sake of discussion 2x2x1m deep. The coping would be at ground level.

Thanks a lot!

 

[bimr]

The common practice for well drilling is to use a mobile truck with outriggers on the terrain. For the typical well, no concrete pad is installed.

 

[Andrew88]

Hi,

The borehole was drilled many years ago but the pump will be replaced with a larger pump and installed at greater depth. There is no way to avoid concrete pads unfortunately due to site restraints

 

[bimr]

Some boreholes include a steel structure above the borehole to lift the pump and pipe string.

How about a better project description of what you are doing rather than playing a game of 20 questions.

 

[cvg]

the pump would be installed using a crane. depending on the size, could be a large crane, not sure how you think you can fit that on a 2x2 meter pad