Solar Energy Profile
Earth Systems Southwest provides a unique set of services to the solar energy industry. Our skills in geotechnical engineering, geology, geophysics, and testing and inspection answer to the needs of the dynamic nature of solar power generation. We understand the challenges presented by project timing requirements, site access restrictions, and environmental and ecological considerations.
In response to accelerated project schedules often associated with solar energy development, our professionals are experienced in completing our services promptly and expeditiously. For projects that are located at remote sites and that are environmentally sensitive, select services can be performed without the need of motor vehicles, using only foot traffic and thereby incurring less impact to the site. Routinely, we interact with specialists such as cultural monitors and biologists to promote the preservation of on-site wildlife and vegetation.
Our services to the solar power industry include those listed below.
Summary Feasibility Reports
Geotechnical engineering consultation during the initial stages of project development can assist in assessing site conditions which may affect construction. Our personnel are experienced with providing such services; findings are presented in a feasibility report.
Preliminary Site Assessments
Typical tasks associated with preliminary site assessments include site reconnaissance to document surface conditions such as ground cover and vegetation, topography, gradients, geologic outcroppings, and soil characteristics; review of previously published reports related to the site; research of literature and data from agencies such as the United States Department of Agriculture; the Federal Emergency Management Agency, the United States Geological Survey, the Natural Resources Conservation Service, and the National Elevation Data.
Information and data obtained from these sources include soil surveys, maps, orthio-imagery and 3D digital elevation data, and seismic safety elements. We then assess potential constraints to development, such as: depth to groundwater, soil plasticity, soil erosion potential, soil expansion, soil corrosion, liquefaction, seismically-induced settlement, fault rupture potential, and porosity.
Geotechnical Engineering Report
Geotechnical engineering reports are prepared to elaborate and further define the constraints addressed in the preliminary site assessment. Our investigations include subsurface exploration and laboratory testing, and address soil conditions, groundwater, and geologic hazards. We provide recommendations for site development including grading, utility trenches, slope stability, foundations, lateral earth pressures and coefficients, mitigation of soil corrosivity, bearing capacity and total and differential settlements, and seismic design parameters.
Chemical analyses of bulk soils samples may accompany the surveys. Sulfates and other salts in soils can attack the cement within concrete and cause it to deteriorate. We perform laboratory tests including Soluable Sulfates and Chlorides, pH, and Electrical Resistivity on the soil samples, and utilize the data to assess the potential adverse affects of soil on concrete. We provide recommendations for mitigation of soil corrosivity.
Geophysical Surveys
We employ nondestructive geophysical methods to evaluate soil properties and subsurface soil and bedrock conditions. Geophysical methods include soil DC electrical resistivity to aid in the design of grounding systems; seismic refraction to evaluate depth to bedrock and rippability; refraction microtremor (ReMi) to detect velocity inversion layers and for site classification; gravity surveys to assess density contrasts, depth to bedrock, and locate faults; ground magnetics and ground penetrating radar to locate buried objects and detect lateral changes in the subsurface; and electromagnetic (EM) for depth sounding and profiling. Seismic refraction in conjunction with ReMi can yield useful information regarding soil engineering properties such as Poissons ratio and maximum shear strength.
Testing and Inspection
Pile Load Testing
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Our technician with a load frame which is used for testing the vertical and lateral loads of steel test piles. |
For solar energy developments that employ photovoltaic (PV) panels mounted on steel I-beam piles, we can perform pile load testing on select test piles. Using information regarding soil properties and subsurface conditions from our field explorations and geophysical surveys, we can determine the optimum driven depths for the piles. During testing operations, physical properties associated with pile driving are observed and measured. Load tests on the driven steel piles are conducted in general accordance with ASTM standards, or as modified by Earth Systems Southwest. The load frame is strategically placed to allow for vertical and lateral testing. The results of these field tests determine the lateral load capacity of the piles, and are compared to the analyses and preliminary recommendations developed in our geotechnical engineering report. The field test data allow for possible design modifications, which can lead to substantial savings in construction costs.
Drilled Piers And Concrete Placement Inspection
For solar energy developments that employ pipe columns supported by cast-in-place drilled pier foundations, we can perform inspection of the drilled piers and concrete placement.
