Geopier Grouted Impact®

The Grouted Impact System provides owners and designers with a ground improvement method that both reinforces and stiffens poor soils, and provides some of the benefits of pile foundations—without the drawbacks. An ideal solution when stone alone does not provide enough reinforcement. This unique Geopier technology (Rammed Aggregate Pier®) provides a stable bearing layer for spread footing foundations; no special load transfer platform required.


The Geopier Grouted Impact System relies on the same specially designed mandrel and tamper foot as the Impact system.  Cement grout is mixed with the aggregate to provide engineering benefits in the following circumstances:

  1. Cohesive or organic (peat, organic silt) soils with low shear strength where the grout serves to inhibit bulging of the pier into the soft layer.
  2. Contaminated soil where the grout creates a low-permeability seepage barrier.

The grout is pumped into the mandrel and introduced within the soil strata where it is needed, the soft cohesive and organic soils where normal ground improvement techniques are either ineffective, impractical or too costly.  Each pier is constructed with heavy downward static force and dynamic vertical ramming.  This results in excellent coupling with the surrounding soils and reliable settlement control with superior strength and stiffness.

Following installation, the RAP elements support standard shallow spread footings, embankments, walls and other structures.  The footing stresses are attracted to the stiff RAP elements, resulting in engineered settlement control.

The design has elements of both pile capacity and ground improvement.  Ground Improvement Engineering has successfully designed a number of Geopier Grouted Impact System projects for significant structures in the Midwest.

Construction Advantages Of Geopier Grouted Impact

  • Significantly stiffer in organic soils and soft clay
  • Clean and rapid installation
  • Standard spread footings are used
  • Does not need a load transfer platform beneath foundations
  • Straightforward, understandable design
  • Improves bearing capacity
  • Reliable