Micropiles can also be used to carry out new construction work and retaining structures such as micro-Berlin-type wall.
Micropiles can bear both compressive and tensile loads and also be used on steep gradients (> 20° from the vertical).
The micropile is supported by a steel bar, a steel tube or an H beam, which is:
Applicable to foundation works, from transmission of tensile loads to angled boreholes, repairs, reinforcements or even retaining works,
Adapts to site constraints: limited height, work from a platform, near existing structures and structures in use, etc.
Adapts to constraints linked to the nature of the ground: stability, drillability, hardness, granulometry, etc.
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.
Ever more innovative and involved in the geotechnical community, Soletanche Bachy continues to develop proprietary tools and techniques and to participate in French and European standardisation.
In order to be always more efficient, Soletanche Bachy has developed the Hi’Drill® process, which allows boring to be carried out more quickly thanks to the combined effects of rotation and translation of a traditional head and those of resonance of a Hi’Drill® head. This process adapts to all types of ground, from the softest to the hardest. It is particularly effective in mixed formations, including through wood and reinforced concrete.