Micropiles are non-displacement piles constructed using high-strength structural elements, usually small-diameter steel casing and/or threaded bar encased in grout and are 300 mm in diameter or less.

Common Uses

  • Support structures and foundations
  • Improve mass stability
  • Transfer loads
  • Earth Retention Sytems

Technical Details

Micropiles are classified by numerous sub-types, each determined by the combination of widely varying drilling and grouting installation processes. Drilling methods include double-head duplex, rotary percussion, continuous grout flush, and rotary with polymer flush just to name a few. Grouting methods include straight tremie injection, dynamic grouting, pressure grouting during casing retraction, and tremie-injection with post-grouting.

Micropiles can be installed in any type of ground and especially in restricted access areas, low headroom interiors, permitting facility upgrades with minimal disruption to normal operations. Micropiles greatly alleviate the quality assurance concerns associated with cast-in-place piling in weak soils. Micropiles are typically used in situations where above-ground or below-ground conditions render the use of conventional deep foundations impractical, too difficult, or too risky to the health of neighbouring structures or services. This technique has been used to support buildings, tanks, modules, process equipment, pipe racks, bridges and other structures.

Keller has designed and constructed many projects across Canada. The vast majority of these projects included at least one static compression load test to 200% of micropile design loading.