Micropiles
Micropiles are small-diameter, high-strength deep foundation elements used to transfer loads into competent ground. Their versatility makes them ideal for underpinning, slope stabilization, and situations with limited access or difficult geology.
Understanding Micropiles
Micropiles are small-diameter, high-strength deep foundation elements used to transfer loads into competent ground. Their versatility makes them ideal for underpinning, slope stabilization, and situations with limited access or difficult geology.
Originally developed for seismic retrofitting, micropiles are now standard practice for challenging foundation and stabilization applications.
This technique is used in our services for:
Drilling 
Grouting 
Soil Nailing Typical Applications
How It Works
Our proven methodology ensures consistent, high-quality results for every installation.
Borehole Drilling
Drill a borehole into competent bearing strata using rotary or percussion methods.
Reinforcement Installation
Install high-strength steel reinforcing bar or casing with centralizers.
Pressure Grouting
Grout the pile to form a high-capacity load-transfer element bonded to surrounding ground.
Connection
Connect piles to the structure or stabilization system using caps, brackets, or grade beams.
Key Advantages
High Capacity, Small Footprint
Micropiles deliver 50-300+ ton capacity from piles as small as 5 inches diameter.
Low Headroom Capability
Specialized equipment operates in spaces as low as 6-8 feet, ideal for basements and under bridges.
Minimal Disturbance
Low-vibration drilling protects adjacent structures and allows work in sensitive environments.
Universal Ground Conditions
Micropiles work in any soil or rock—from soft clay to hard granite—adapting to variable conditions.
Immediate Load Capacity
Grout reaches design strength within days, allowing rapid load transfer to the pile system.
Technical Considerations
Soil/Rock Conditions
Micropiles work in all ground conditions. Cased piles for caving soils; uncased for stable rock. Bond length in competent material determines capacity.
Groundwater
Drilling and grouting methods adapted for wet conditions. Hollow-bar systems allow simultaneous drilling and grouting in difficult ground.
Load Capacity
Capacity depends on pile diameter, reinforcement, grout strength, and bond length. All piles load-tested to verify design capacity.
Spacing
Pile spacing determined by load requirements and group effects. Minimum spacing typically 3 pile diameters center-to-center.
Installation Method
Rotary or percussion drilling through overburden into rock. Reinforcement placed with centralizers, grouted under pressure from bottom-up.
Equipment Used
- Low-headroom drill rigs
- Rotary and percussion drill tooling
- Grout mixing and pumping equipment
- High-strength reinforcing steel
- Load testing equipment
Limitations
- Higher cost per unit load than driven piles
- Requires competent material for bond zone
- Drilling spoils require management
- Group effects may reduce capacity
Technical Specifications
System Variations
Cased Micropiles
Steel casing provides structural capacity and prevents borehole collapse in unstable soils.
Best For:
- Soft soils
- Caving conditions
- Lateral load resistance
Uncased Micropiles
Reinforcing bar grouted directly into stable rock for economical load transfer.
Best For:
- Competent rock
- Vertical loads
- Cost-sensitive projects
Hollow-Bar Micropiles
Self-drilling hollow bars allow simultaneous drilling and grouting in collapsing ground.
Best For:
- Caving soils
- Difficult drilling conditions
- Emergency applications
Tension/Compression Piles
Micropiles designed for uplift, compression, or combined loading as required.
Best For:
- Seismic retrofit
- Transmission towers
- Retaining structures
Integration With Other Systems
Tieback Anchors
Micropiles provide vertical support while tiebacks resist lateral loads in retaining systems.
Learn More
Soldier Pile Walls
Micropiles can serve as soldier piles in confined spaces where driven piles cannot be installed.
Learn More
Pressure Grouting
Ground improvement grouting enhances micropile capacity in weak soils.
Learn MoreExample Project Types
- Building foundation underpinning
- Bridge pier reinforcement
- Landslide stabilization
- Retaining wall foundations
- Historic structure preservation
- Seismic retrofit
- Transmission tower foundations
- Industrial equipment foundations
Our Work in Action
Why Choose Rock Supremacy for Micropiles
Specialized Access Equipment
Low-headroom rigs and steep-terrain platforms allow installation where standard equipment cannot operate.
Proven Track Record
Successful micropile installations for DOTs, railroads, and industrial clients across challenging sites.
Advanced Grouting
Pressure grouting techniques maximize pile capacity and ensure complete bond zone development.
Complete Load Testing
All piles tested to verify design capacity with full documentation for owner records.
Integrated Solutions
Micropiles combined with tiebacks, drainage, and other techniques for comprehensive stabilization.
Our Work
See how we've applied this technique and others to solve real-world geotechnical challenges.
Bingham Canyon Mine Support
Highwall stabilization in one of the world's largest open-pit mines to ensure safe ongoing extraction.
I-70 Corridor Stabilization
Installed 50,000 sq ft of high-tensile mesh and performed extensive scaling after a major weather event.
Lava Hot Springs Slope Stabilization
Multi-phase slope stabilization project protecting the historic hot springs resort and Highway 30 from an active landslide.
Micropiles FAQ
Client Testimonials
Trusted by DOTs, engineering firms, and property owners nationwide.
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Related Techniques
Explore other engineering methods we use to deliver comprehensive geotechnical solutions.
Micropile Underpinning
Micropile underpinning strengthens existing foundations by transferring loads into deeper, more competent soil or rock. This technique is essential for repairing settlement, stabilizing structures in landslide areas, or supporting new loads for renovations and expansions.
Pressure Grouting
Pressure grouting strengthens ground, fills voids, and reduces water infiltration by injecting grout into soil, fractured rock, or void spaces. This technique supports slope stabilization, foundation improvement, landslide remediation, and structural repairs.
Soldier Pile Walls
Soldier pile walls are proven earth retention systems for stabilizing deep excavations and steep slopes. Steel beams installed at intervals with lagging placed between them provide flexible, economical support that adapts to site constraints.
Tieback Anchors
Tieback anchors provide active lateral reinforcement for retaining walls, excavation support systems, and slope stabilization by transferring loads deep into stable ground or rock. These post-tensioned elements are essential for deep excavations and high-load applications.