Micropiles, or minipiles, are foundation structural elements constructed using high strength, small-diameter, typically 6 to 12” (150 to 300 mm), steel casing and/or threaded bar, which are encased and surrounded by grout within soil or rock. Since micropiles can be installed with relatively small drilling equipment, they are an effective support for applications with restricted access and/or low headroom.
They permit facility upgrades with minimal disruption to normal operations.
Grouting can be achieved by tremie grouting, pressure grouting during casing retraction, and tremie-grouting with post-grouting. Post-grouting within the bond length can increase frictional forces with surrounding soils, thus achieving greater capacity.
Micropile capacities in excess of 400 kips (1,780 KN).