Phone: 425.415.0551

Fax: 425.415.0311

Email: info@riley-group.com


Riley Group Corporate Office

17522 Bothell Way NE

Bothell, WA 98011


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Wind Farm

Posted on

waubrawindfarm14-05-0737

RGI is contracted to provide geotechnical engineering services to what will be the largest wind project in the Pacific Northwest, ultimately producing over 1,400 megawatts of energy.  Once complete, this seven phase project will include 690 wind turbines across Garfield and Columbia Counties.

T-33 looking southeast

RGI completed the first phase of this project  in 2009, when we performed over 170 borings and test pits to characterize soil conditions. The second phase is currently under construction.  As part of the geotechnical engineering for the second phase, RGI completed 145 borings in 15 days over 5 weeks. Recommendations were prepared and a draft report was submitted 10 days after the drilling was completed. The variable soil conditions for the second phase, include basalt in the northern portion of the site and deep silt on the southern portion of the site. Such conditions have made foundation and roadway development a challenge for the design team throughout the project. RGI continues to offer feasible alternatives to turbine foundation design and subgrade preparation complicated by the site grading and a change in the turbine foundation numbering.

Geotechnical services included geotechnical engineering reports for the first and second phase of this project, including:

  • Soil conditions at each foundation location
  • Foundation design recommendation for the turbines, met towers, and substations
  • Foundation subgrade preparation
  • Site preparation and grading
  • Soil corrosion
  • Rock quality for the quarry sites

Geotechnical services included construction Monitoring during the second phase of the construction, including:

  • Foundation overexcavations
  • Review of reports by others and providing foundation letters for turbine sites
  • Construction of modular block for road intersection widening