Working in the field brings a lot of unforeseeable circumstances and challenges, I am writing this article today to just share with you a trouble I have recently faced while working as a Project Engineer here at your site in Metro Bus Project.
We here were working on one of the flyover which have 12 piers having on average 9 piles underneath. We here are using Cast-in place friction piles and for concreting we were using the tremie method of concreting.
Mostly while working for piles in underwater level we use the tremie method. For tremie method after boring with auger upto required dia and depth. We lower the tremie pipe having conical top at the upper end. After attaching suitable no. of tremie pipes with the help of threads at the end. We just lowers the schut of the transit mixture to pour concrete through the upper conical portion into tremie pipe and then into bore hole. The concrete through pressure and weight displaces the water at the top and with this procedure the concreting of pile is done.
For lowering the tremie pipe we use mechanical crane rather than hydraulic crane the reason being that we in the concreting requires to shake the tremie pipe after few and while so that tremie pipe can’t stuck in. While concreting we removes the tremie pipe one by one and requires only the top portion to be dipped in the top of the concrete.
Tomorrow we faced a problem in which the tremie pipe got stuck in and as it is very costly pipe we don’t want to loose our pile as well as our tremie.
Following are some of the procedures we adopted and must be adopted in order to get out of such trouble.
1) Make sure to give shake the tremie pipe after few and while.
2) If the tremie pipe got stuck with crane use the excavator of crawler mounted type it will help
3) Use few liters of retarder admixture to increase the setting time it will help as well.
4) You can also use the concrete pump negative suction method, while the pump runs inversely it will help to create suction within the tremie pipe that will help the concrete to come up in the tremie pipe and thus loosen concrete a bit.
5) Above all make sure to use safety precautions on the spot.