Micropiles are small-diameter piles, typically 80 to 300 mm, composed of a bar, steel tube, or steel reinforcement that forms the load-bearing core. This core is typically coated with injected cement grout to form the bulb. This injection promotes the work by lateral friction of the shaft. However, elements driven by impact or vibration, with a diameter no greater than 150 mm, are also called micropiles. “Pali-radicci” or root piles appeared in the 1950s to solve the problems of underpinning buildings or structures. These were small-diameter boreholes (3 inches or less) into which a steel rod was inserted and injected with cement grout.

The machinery used to execute micropiles has advantages over that used for piles, as it is more accessible and maneuverable in confined spaces, reduces movement during execution and therefore deformations relative to neighboring structures, is adaptable to hard, heterogeneous, and obstructed soils, and maintains verticality well. However, it is not as suitable for saturated soils or those with a water table higher than the lower elevation of the foundation.