Piles and micropiles

Use of Micropiles and Steel Piles

Description
Micropiles are deep foundation elements with a typical diameter of less than 300 mm, used when:
•The available space is limited (e.g. urban renovations),
•The ground is unstable or stratified,
•High compressive and tensile strength is required,
•We work on existing buildings (under foundations).
Steel poles, often tubular, are used in similar contexts, with the advantages of speed of installation, high mechanical resistance and adaptability to dynamic loads (e.g. seismic).
Pipe Couplings
  • To ensure structural continuity and sealing during injection, the pipes are connected using:
    •Male-Male + Sleeve Coupling: two male ends joined by an external threaded sleeve, ideal for maximum mechanical resistance.
    •Female-Female Coupling + Nipples: two female ends connected via an internal threaded nipple, useful for reducing the total external diameter.
    •Male-Female Coupling: direct joint without intermediate elements, quick to assemble and compact.
    All threads can be made with 1, 2 or 3 starts to speed up the screwing time on site.
Drilling and Valve Fitting
We drill precision holes for the installation of injection valves (manchon), with controlled positioning along the pipe.
Available valves:
•Standard valves with 12 mm hole diameter (pressure up to 3–5 bar),
•High pressure valves with 16 mm hole diameter (pressure up to 20 bar),
• Sleeve valves – for repetitive and selective injections, ideal for type III and IV micropiles according to the EN 14199 standard and the Franki/Fayat classification.
Accessories Products
• Injection heads – for quick connection to pumping systems,
•Drill bits – for drilling in rock or compact soil,
•End caps – for closing the tube,
•Protective caps – for threads during transport and installation,
•RDT Concentric Drilling Systems – welded directly onto the pipes, both recovery and permanent. For more details, visit our dedicated page: RDT Casing System Advance.

Types of Micropiles
EN 14199/Franki/Fayat

Type II – Gravity Injection

The hole is filled with gravity-fed cement mortar after the reinforcement has been installed. Suitable for stable, unfractured soils. Low injection pressure ( < 1 MPa). Economical solution for medium-criticality works.

Type III – Global Unit Injection (GUI)

  • After the setting of the coulis de gaine, a single global injection is performed at a pressure ≥ 1 MPa (up to 4 MPa). The armor can be a metal tube equipped with manchettes. Ideal for medium-complex terrain and structural works.

Type IV – Selective Repetitive Injection (IRS)

Injection liner by liner, at pressure ≥ 1 MPa (up to 4 MPa). Maximum control of mortar spread. Used in fractured, unstable soils or for critical works (e.g. underpinnings, slopes, seismic zones).

Interconnected Walls and Inlets

Piles are inclined or horizontal micropiles installed to counteract lateral thrusts (e.g. bulkheads, tie rods) or stabilize excavation faces.

Interconnected walls are a series of piles/micropiles interconnected by girders to form a continuous wall. For an in-depth technical explanation, application diagrams, and case studies, consult our dedicated guide: Interconnected Walls.