air lifting technique

[kkr90]

hi,
some one explain the process of air lifting technique in piles and why it is used &how to do that

 

[aeoliantexan]

In my experience an air lift is a vertical pipe with a smaller pipe or hose beside it and a U-shaped tube to jet the air up into the big pipe. The assembly is lowered to the bottom of a water-filled excavation or a slurry-filled pier hole. When the air is turned on, water and air will spew out the top, bringing mud, gravel, even cobbles with it. It is a tool for cleaning the bottom of a pier or a cofferdam. It can also be used to remove slurry that has become too sandy while adding fresh slurry at the top.

 

[kkr90]

thanks for ur reply sir ,
can u explain about the causes and reasons for choking in the piles?
and also explain about the remedial measures for it

 

[aeoliantexan]

I'm not sure what you mean by "choking". Can you give us more information, such as the type, diameter, and length of the piles and what the "choking" involves?

 

[kkr90]

what i came to know from the field is while concreting (bored cast-in-situ pile)using tremie pipe if the concrete does not go through or if it get struck up in the middle of concreting they call it as a choking

ours is 1.2 m dia,and depth is 45m

 

[BigHarvey]

There is no relation between your "choking" and air lifting !Next time start another post !

If concrete doesn't go through the tremie pipe, causes can be
- diameter of tremie pipe is too small ( 8 inches ID minimum)
- too much embedment of the tremie pipe in the concrete ( min is 2 to 3 m and actual should be kept close from min )
- slump of concrete is too small (ideal is around 180 mm, with 130 mm likely to "choke")

 

[chicopee]

In regard to the tremie pipe, I am assuming that you are using a concrete pump to deliver the concrete under water and as the height of concrete column is getting higher under water, you should also raise the tremie pipe while its outlet remain slightly embedded in the poured concrete so that no water gets trapped under the poured concrete; it's a procedure learned in the field by those who have not had prior experience with this technique.

 

[PEinc]

This thread is about airlifting. For an explanation, see Chapter V of Harold V. Anderson's Underwater Construction Using Cofferdams, Page 158, Airlifts, from Best Publishing Company, 2001,

http://www.bestpub.com.

There is a sketch and several paragraphs describing the operation.

http://www.PeirceEngineering.com