A pile is one type of building foundation. Piles are used when the soil near the ground surface is not strong and the weight of the building must be carried by deeper soil layers. The strength or bearing capacity of the soil can be measured using a cone penetration test.
Piles can be prefabricated and driven into the ground using a vibrator or a diesel pile driving rig supported on a drag line excavator, or can be formed in situ in a bore hole.