Micropiles are drilled and grouted piles reinforced with high-strength threaded bar to transfer loads to a competent soil or rock layer.
Micropiles are drilled and grouted piles reinforced with high-strength threaded bar to transfer loads to a competent soil or rock layer. Typically, micropiles are classified as 2.5″ to 12″ in diameter and, due to the small pile size, are often installed with permanent steel casing to provide increased lateral capacity. A micropile is a frictional foundation element developing capacity through the bond between the cement grout column and the surrounding soil/rock which provides resistance in both tension and compression. Micropile capacities vary depending on the micropile diameter, reinforcing size, soil conditions, and grouting procedure. The design adhesion between the grout and soil can be increased by varied installation and grouting techniques. Micropiles can be installed using air or mud rotary drilling, impact driving, jacking, vibrating or augering machinery. The wide range of micropile drill tooling available allows flexibility to install in many ground conditions, from soft clays to hard bedrock.
Advantages of micropiles:
- High load capacity in both tension and compression.
- Easily socketed into hard rock and can penetrate through subsurface obstructions and/or boulders encountered during installation.
- Minimal vibration and disturbance to adjacent structures in close proximity.
- Can be installed in limited access and low headroom work areas.
- Installation techniques allow for elevated groundwater or caving soil conditions.
- Ideal for foundation underpinning or retrofit applications due to limited access, low headroom and close proximity capabilities.