Terrapiers™

What are Terrapiers™?

Terrapiers™ are rammed aggregate columns, acting as structural elements designed to reinforce a compressible soil mass, allowing shallow foundation support with minimal settlement.  Although Terrapiers™ are similar to other aggregate columns, such as the Geopier® Rammed Aggregate Pier™, a vastly improved design methodology has been developed.  Terrapiers™ are constructed by removing or displacing soil to create a cavity in the ground, penetrating soft zones, and then backfilling with aggregate from the bottom up using vibratory and displacement techniques.  Very high lateral stresses are generated by the compaction action in the aggregate, resulting in a high-modulus element surrounded and underlain by pre-strained soil.

The Terrapier™ Advantage

What are Typical Applications?

The largest application of Terrapiers™ is for foundation support in old fills, however Terrapiers™ can also be utilized for support of building slabs, tanks, and M.S.E. walls.  In addition, Terrapiers™ can be used to stabilize exisiting landslides or to prevent future landslides.  Terrapiers™ have also been used to decrease the susceptability of soils to liquefaction during an earthquake.

What are Design Considerations?

The behavior of Terrapier™-reinforced soils is a complex interaction between the relatively stiff Terrapier™ and the more compressible soil matrix.  Historically, analyses of traditional stone column systems have ranged from experience-driven empirical estimates to complex finite element analyses.  In a soil layer reinforced by Terrapiers™, the compression is a function of the foundation shape, load intensity, Terrapier™ geometry (depth and diameter of the Terrapiers™), spacing of the Terrapiers™, and the compressibility characteristics of both the aggregate in the Terrapiers™ and the surrounding soil matrix.

What Soils are Suitable?

As with conventional stone columns, Terrapiers™ can be utilized in most soil types. However, the largest application of Terrapiers™ is for support of foundations in old fills.  Terrapiers™ can also be used in virgin soils, including silts, clays, and granular deposits.

_{Geopier® and Rammed Aggregate Pier™ areregistered trademarks of the Geopier Foundation Company.}