A licensee of Geopier and The Geopier Rammed Aggregate Pier™ System since 2008.
The system is a patented proprietary ground improvement system that comprises a series of piers constructed of uniformly graded aggregate (or stone) installed using specialized equipment.
Aggregate Piers are a series of crushed stone pillars placed with a vibrating tool into the soil below a proposed structure. This method of ground improvement is also called vibro replacement. Such techniques increase the load bearing capacity and drainage of the soil while reducing settlement and liquefaction potential. Stone columns are made across the area to be improved in a triangular or rectangular grid pattern. A layer of compacted gravel is then put over the top of the piers, ready for the construction of a structure. They have been used in Europe since the 1950s, and in the United States since the 1970s. Column depth depends on local soil strata, and usually penetrates weak soil.
Stone Columns/Rammed Aggregate Pier – Ground Densification Solutions
A technique that compacts granular soils and rearrange the soil particulars into a denser state. The compaction is attained using depth vibrators, typically suspended from a crane or mounted on piling equipment.
How do Rammed Aggregate Piers improve the ground?
Rammed Aggregate Piers help to limit the amount and consequences of liquefaction by:
• Displacing soil laterally to densify the soil and increase soil stiffness
• Reinforcing the soil creating a stiff composite soil mass
By achieving this, the non-liquefying soil crust is thickened and stiffened to reduce the likelihood of undulations, tilt and uneven ground surface subsidence from liquefaction of the underlying soil layers.
How are Rammed Aggregate Piers constructed?
Rammed Aggregate Piers are installed by experienced contractors, using specialist equipment involving an excavator with a vibrating mandrel attachment. An excavator or tele handler continually loads stone into the hopper, feeding it down the mandrel and into the ground. The stone is compacted using a ramming and vibrating action to form a stiff, high-density, vertical aggregate pier within the ground.
What are the advantages of Rammed Aggregate Piers?
An advantage of Rammed Aggregate Piers is that no dewatering or excavation is required for construction. They also typically have a short construction period.
What soils suit Rammed Aggregate Piers?
Rammed Aggregate Piers are best suited to sandy soils. A greater concentration of Rammed Aggregate Piers are required when used in siltier soils.
Uplift Anchors RAP system
The uplift anchor assembly extends from the bottom of the pier to the ground surface where it is structurally connected to the shallow foundation. The uplift resistance provided by the Geopier systems eliminates the need for deep foundations or over-sizing of shallow foundations. Lateral resistance of Rammed Aggregate Pier® systems is provided by increased composite friction angle that results in an increased composite friction coefficient for sliding resistance at the base of foundations.
Construction of the Geopier ground improvement solution using vertical ramming energy results in friction angles of 50 degrees. This provides significantly improved design bearing pressures of 5 to 10 ksf or more depending on soil conditions. The improved bearing pressure reduces footing sizes, saving time and money on your project.
Grouted Columns
The addition of grout to the Rammed aggregate piers system stiffens the pier and provides improved long-term confinement. During installation, cement grout is introduced into the hollow mandrel and filled to a prescribed depth. Aggregate is then placed into the mandrel and the grout covered aggregate is used to form the grouted RAP element. The ramming of the grouted aggregate causes pre-stressing and pre-straining of the matrix soils improves the density of the granular materials and increases the lateral stress in surrounding soil. The grout binds the compacted aggregate together and strengthens the pier through weak soil zones or organic layers.
Interested in Stone Columns / Rammed Aggregate Piers?
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