Amherst Wind Turbine Geopier® Rammed Aggregate Piers

THE PROBLEM

The Amherst Wind Power Project involved the construction of 15 wind turbines that have the capability to generate enough power to supply 10,000 homes. The ideal location for these wind turbines was on the Tantramar Marsh in Amherst, Nova Scotia but the soil conditions consisted of very deep soft clay which was not suitable for their foundations. Driven steel piles is the traditional method to provide deep foundations but this process is very expensive and time consuming.

THE SOLUTION

The Geopier® Rammed Aggregate Pier Intermediate Foundation System was chosen as an alternate solution to driven piles for some of the turbines where the soil conditions were conducive. The choice resulted in substantial savings and accelerated the construction schedule due to the speed of installation in any weather. This unique installation process involved pre‐augering 30‐inch diameter holes through the soft clay and ramming 12 inch thick lifts of well graded aggregate with a beveled tamper to form very stiff, high‐density aggregate piers. This ground improvement technology increased the bearing capacity of the soil and provided settlement control within acceptable standards for the turbine foundations.