What is a Geopier?
Geopier is a term used in engineering in which stiff rock columns are drilled deep into the earth’s surface, down to a hard non yielding depth. They are used to support a building foundation and reinforce the soil when the existing ground is unstable, wet or unsuitable for building construction.
The geopier process begins when the soils engineer visits the job site. They dig a test pit and take a core sample of the existing ground. The sample gets tested for strength, liquid limit, compressibility, organics, and structural integrity. After the soil is determined unsuitable, a geopier may be the cheaper option for support. The site must be cleared and grubbed for the process to start. A footing blueprint must be designed so the geopiers may be strategically placed directly below the footing. A 50 to 100 foot column is drilled in designated spots. The shaft is then filled with 2 to 4 inch crushed rock and then rammed into the bottom of the shaft with a hydraulic hammer. After this layer is compacted into the bottom, layers of well crushed rock are rammed to the top of the geopier shaft. The ramming of the rock creates a very stiff, dense rock pier that expands the drilled shaft and reinforces the soil.
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There are many advantages of using a geopier. The most obvious is that it reinforces the unstable soil, which creates a much greater support capacity. There have been many proven examples that this has worked, and ensures high levels of reliability. The use of geopiers is very economical and will often results in a twenty to fifty percent cost savings. It is a very fast and efficient installation process, this creates shorter construction times. When recycled concrete and materials are used this can be very eco-friendly.
I have seen a geopeir being used. It was at the Sorenson Reasearch Park on Riverboat Road in Tayorsville. The water table ws high and a river flowed through the site. This process greatly helped and was able to make the building construction possible.