Write a note on under-reamed piles.

For the construction of under-reamed piles, a borehole is formed into the ground and then concreting it either with the help of a casing tube or without a  casing tube. Their construction technique is different than cast-in-situ piles.

These are suitable where: 

1. Vibration and noise caused by driving piles are to be avoided.
2. Hard strata is deep such that it cannot be reached by driven piles.