STRATIGRAPHICS has provided CPT and CPTU-EC-S (Cone Penetration Test with soil Electrical Conductivity and shear wave velocity measurements) exploration services for numerous wind turbine farms throughout the Midwestern US. We have performed work for RMT WindConnect and AMEC, among others. The work was to provide geotechnical data for design of the wind turbine foundations. We have performed CPT at nearly 1000 proposed wind turbine foundation locations.

STRATIGRAPHICS CPT services provide a very powerful tool for these fast paced, cost sensitive projects. The CPT measurements provide data for geotechnical design of the turbine foundations. The soil electrical conductivity measurements provide data for electrical grounding of the turbines, additional lithologic discrimination, and information about soil moisture levels. The CPT-EC measurement is often substituted for Wenner array measurements, as the CPT-EC measurement is acquired at each turbine location as a continuous function of depth, at a very low cost. The CPT seismic shear wave measurements are used for vibration analysis of the foundations under the influence of the rotating wind turbine blades.
Our very high levels of in-the-field geotechnical expertise allow each turbine foundation location to be immediately evaluated as testing is performed. We have identified locations with poor local foundation conditions for our clients. This has allowed our clients to move turbine locations to alternate locations during the exploration program, and have these alternate locations to be tested, before any equipment is demobilized from the project site.

We have integrated GPS logging of both rig daily travel, and coarse (+/-) 5 meter CPT sounding locations concurrent with all exploration work. The daily GPS travel logs can be used to verify property access conditions, possible trespass and crop damage. The location specific GPS is both useful for QA of actual test performance at the proper location, and can be used if location stakes have been lost or vandalized.

We typically provide CPT exploration using our high capacity, high productivity truck mounted CPT rigs for these projects. We mount agricultural flotation tires on the rigs to enhance rig mobility for off road travel to the turbine locations. Wind turbine work is often performed during winter months, where the ground is frozen, allowing good off-road access. Our rigs are fully enclosed which allow work to continue during extremely inclement weather. STRATIGRAPHICS worked on the Prairie Wind Project, south of Minot, North Dakota in bitter winter conditions in February and March of 2009. Snow drift depths exceeded 10-15 ft in places, with wind chills below -50 degrees F.

Some wind turbine projects we have worked on include: Prairie Wind (RMT), Minot, North Dakota; Big Sky (RMT), Princeton, IL; Noble Thumb (RMT), Bad Axe, Michigan; Fowler 2 (RMT), Fowler, Indiana; Conception Junction (RMT), Missouri; Rockport Municipal (RMT), Missouri, Lost Creek Ridge (RMT), Missouri, Bluegrass Ridge (RMT), Iowa, Endeavor (RMT), Walnut Ridge (RMT), Illinois; Crescent Ridge 2 (AMEC), Illinois; Harvest Wind (RMT), Michigan, Blue Sky (RMT), Wisconsin.

Client company names are provided for identification of projects only, and do not imply or constitute endorsement or recommendation for our services

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