Geopier® GeoSpike℠ System

Geopier’s GeoSpike℠ system is a patented, low-cost method that will reinforce soft soils and provide a high strength, superior level of performance without removing railroad tracks, ties or ballast.

The GeoSpike system is comprised of a set of polymer shells, installed by licensed Geopier crews, between rail ties. Aggregate is then placed within the confining shell and compacted. The dynamic loads from the passing rail cars arch through the ballast and are effectively transferred through the GeoSpike down to a stronger bearing layer.

This is a quick, intermediate solution that will eliminate the need for over-excavation-based subgrade repair. It has the ability to safely strengthen railway subgrades while minimizing downtime to rail operations.

Similar to other Geopier Rammed Aggregate Pier® solutions where direct vertical ramming energy compacts high-quality aggregate to form high stiffness elements — GeoSpike provides support capacity, increased bearing pressure and settlement control.

Geopier Geospike Design/Construction Process

Geopier GeoSpike solutions are designed to reinforce weak rail subgrade soils to increase the track subgrade modulus and reduce deflections that occur under dynamic loading conditions.

  1. Geopier licensed crews place the GeoSpike on the specially designed tapered
  2. mandrel and drive the shell into the ground using a strong static force
  3. augmented by high-frequency, vertical ramming energy. The patented shape
  4. of the GeoSpike shell is designed to squeeze between closely spaced railroad
  5. ties and expand back out once driven to the design depth. To prevent damage
  6. to the shell during routine ballast maintenance, the top of the shell is
  7. embedded below ties to depths of 12 to 18 inches.
  8. After driving to the design depth, the confining shell remains in place. The
  9. shell is then backfilled with small diameter aggregate placed in lifts and
  10. compacted with the driving mandrel. The process creates dense, high
  11. stiffness elements that offer superior strength and performance by
  12. transferring dynamic loads from passing rail cars through the poor subgrade
  13. down to a suitable bearing layer.
  14. The installed elements significantly improve the subgrade modulus to
  15. effectively decrease the cyclic deflections of the track from passing wheel
  16. loads — reducing the permanent settlement of the track over its lifetime.

Geopier GeoSpike Applications

  • For rail owners, contractors, and designers
  • Improve railroad track subgrade modulus without costly repairs and disruption
  • Decrease permanent track settlements.

CASE HISTORY: Canadian National St. Clair Subdivision – Sarnia, ON

The Geopier GeoSpikeSM system was used to reinforce the subgrade at a consistently problematic section of track which reduced dynamic deflections of the railway by more than 60% without removing track, ties or ballast.


Canadian-National (CN) maintenance crews are familiar with this section of rail in rural Ontario, south of Sarnia, due to the frequency of re-ballasting and subgrade repairs that plagued this section for many years. CN chose the Geopier GeoSpikeSM system to remediate this problem area for a 55m (180 ft) section of track. This section had chronic settlement and deflection issues resulting from very soft and wet subgrade conditions below the ballast. Deflection monitoring of this track section showed that more than 75 mm (3 in) of deflection had occurred since the previous repair. The soil stratigraphy below the track structure consists of a mixed ballast and soils stratum 1.4 to 1.8 m (4.5 to 6 ft) thick, overlying a medium stiff clay deposit becoming stiff to very stiff at depths of 2 to 3m (6.5 to 10 ft).

Geopier Solution:

The Geopier solution for this project consisted of 1.2 to 2.1m (4 to 6 ft) GeoSpike elements installed so that the GeoSpike tops were 0.3 to 0.6m (1 to 2 ft) below the bottom of the existing ties. The GeoSpike elements were installed between the rails in pairs, spaced at every other tie to resist a Cooper E-80 derived working load of 15 kips (67 kN) per GeoSpike. More than 120 GeoSpikes were installed with a hi-rail mounted excavator without removing track, ties, or ballast in less than 2 days. After GeoSpike installation, the work area was re-ballasted and the rail lines were re-aligned.

Project Team:

Owner: Canadian National
Geotechnical Engineer: Journeaux Associates
Installer: GeoSolv Design-Build, Inc.


Now read about the Geopier SRT® system for slope reinforcement.