These include Multi-Analysis of Surface Waves (MASW), Ground Penetrating Radar (GPR), Electrical Resistivity (ER) surveys, Thermal Resistivity (TR) testing, Pile Load Testing (PLT) and Electrical Imaging (EI). We only subcontract leading, reputable testing firms to perform these services and have established working relationships across North America. The reports of such specialty testing are included as appendices to the geotechnical report which we produce.
MASW Surveys
For utility-scale wind projects, MASW surveys are typically performed at a subset of WTG locations, preferably as part of the preliminary geotechnical investigation and immediately after drilling the preliminary investigation borings. They should be scattered around the project area with a conscious effort to capture the variability of geotechnical settings across the project area.
ER Surveys & TR Testing
We recommend that electrical and thermal resistivity testing be performed as soon as the layout of the collection system and the substation location have been defined. This should preferably coincide with the preliminary geotechnical investigation to allow for changes in the collection system configuration if necessary based on the ER and TR test results.
Ground Penetrating Radar
For utility-scale solar projects, GPR is useful in detecting depth of bedrock or assessing abundance of cobbles, if driven or helical piles are being considered.
Pile Load Testing
Geotechnical investigations for solar projects often involve pile load testing to characterize the resistance of piles, across the project area, to uplift, lateral and compressive loads applied by the PV racking structures. Such testing is essential to achieve optimized foundations for the facility.
Electrical Imaging
We sometimes recommend electrical imaging to assess presence of voids, particularly below wind turbine foundations. The results of such imaging lead to recommendations relative to potential grouting to fill such voids.