Bored piles are embedded deep underground, so it is impossible to verify the quality of the inspection by the naked eye. Due to the peculiarity of concrete pouring technology in place in boreholes, the presence of bentonite drilling fluids is of great importance. Pile quality is difficult to control. And bored piles can be subject to change due to wall collapse, bentonite, layering or impurities due to uneven concrete slippage or inadequate spillage. Therefore, in addition to monitoring closely during the construction of bored piles as well as checking the size and depth of the hole, the level of sand deposition, drilling mud, concrete and steel pile, concrete mass. Experiment to check the quality of bored piles after construction is still necessary to accurately assess the actual quality of bored piles, ensure the progress of the project and ensure safety. Testing method of bored pile quality:

- Static compression testing method: applied for piles and bored piles

- Ultrasonic bored pile experiment: applied only to bored pile / barette pile / wall in soil

- Small PIT (PIT experiment): applied to pile and bored pile.

- Large deformation test PDA (PDA experiment): applied to piles and bored piles.

- Core drill or pile tip: applies only to bored piles / barette piles / walls in the soil.