Methods of execution of bored micropiles are based on the use of compact drilling machines which allow continuous drilling in direct and/or reverse circulation with a drilling fluid such as air, water, bentonite mud, polymers or cement grout. In order to optimize production, it is common for the reinforcement to comprise a hollow bar or a tube, “self-bored” using a lost tool, allowing drilling fluid and sealing grout to flow through its centre.
In the case of displacement micropiles, the load-bearing component made of steel, iron or precast concrete may be installed by vibro-driving or driving.
When underpinning the foundations of a building, the loads may be totally or partially transferred by jacking to control the effects of differential movements over time. The vertical deformations of micropiles are greater than those of piles of equivalent bearing capacity.