Materials Lab - Geotechnical Services

WSDOT is nationally known for its geotechnical engineering and engineering geology expertise. Geotechnical Services staff provide a lead role in developing and setting national public sector standards of practice for the geotechnical profession. By providing the following services, we ensure that the soil or rock beneath the ground surface can support the loads and conditions placed on it during road construction and maintenance:

  • subsurface field investigations
  • geologic site characterization
  • laboratory testing of soil and rock
  • structure foundation and retaining wall design
  • soil cut and fill stability design
  • rock slope design
  • unstable slope management
  • unstable slope mitigation due to rock fall, landslides, debris flow, etc.
  • material source evaluation (pits and quarries)
  • long-term site monitoring for geotechnical engineering purposes
  • support to regional construction staff regarding geotechnical issues and contractor claims
  • support to regional maintenance staff when geotechnical problems occur such as landslides, rock fall, earthquake or flood damage

Requirements for a geotechnical investigation

Your project will very likely need a geotechnical investigation and design if it will involve:

  • significant cuts and/or fills
  • unstable ground (e.g., landslides, rockfall areas)
  • crossing wetlands or otherwise soft ground
  • structures such as bridges, retaining walls, or large hydraulic/drainage structures

If the project contains any of the above elements, contact Geotechnical Services early in the project development to provide input. 

Request a geotechnical investigation

Start early to prevent potential delays! Depending on the following factors, it could take two to six months to complete the work:

  • Federal, State and local permits
  • right of entry needs
  • overall complexity of the project
  • timely availability of the necessary site data from the region project office
  • overall Geotechnical Services workload

To request a geotechnical investigation and design, contact  Geotechnical Services.

Note:  If your project involves bridge foundation design, contact Bridge and Structures to request a geotechnical investigation.

Manuals and reports


WA-RD 791.1
Earthquake Ground Motion Selection
Full Document (pdf 2.26 mb)
Authors:  Steven L. Kramer, Pedro Arduino, Samuel S. Sideras.
Originator:  Washington State Transportation Center (TRAC)
Publication Date:  Thursday, May 31, 2012

Download SigmaSpectraW (zip, 22 mb)
Select Save, Open, Open the bin folder, then click on the SigmaSpectraW.exe to run.

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