Subsurface Infrastructure, Geology, and Natural Hazards
Geoscy uses geophysical techniques, such as electromagnetic induction locating (EML), ground-penetrating radar (GPR), and electrical resistivity imaging (ERI) to locate, map, and assess:
- Utilities: water mains, electrical cabling, pipes with storm-water, drinking water, wastewater, and natural gas
- Infrastructure: storage tanks, trench shields, retaining walls, old foundations, old transportation materials
- Foundation conditions: rock and sediment types, depth to competent materials, voids, wetlands
- Slope stability: likely failure zones, zones of excess water content, estimation of rock/soil shear strength
- Ground subsidence: the distribution of wet and organic soils, weathered and fractured rock zones, groundwater flow patterns
- Sinkholes: width, depth, collapse history, collapse mechanisms
We use high-precision GPS to track our EML, GPR, and ERI surveys and collect short cores from sites to increase ground-truth. Typical deliverables include a report with projected maps and subsurface cross-sections that show original data and interpretations for utilities, infrastructure, substrates, and/or other conditions.
Accidental damage to previously unknown infrastructure during subsurface construction and lack of knowledge about the condition of utilities cause unanticipated delays that increase project costs and can threaten public safety. Lack of information about foundation conditions, such as the location and depth of shallow bedrock, weathered bedrock, wetland sediments, clay layers, and sinkholes prior to subsurface construction can lead to project redesigns, structural collapse, and property damage.
Geoscy assessments reduce these problems and make subsurface construction more efficient leading to better construction outcomes. Our assessments reduce the cost of test-pit/coring in pre-construction investigations and increase spatial coverage of a construction site.
Geoscy is one of the few companies that offer a range of EML, GPR and ERI geophysical surveys and have the experience to expertly interpret the results. Geoscy assessments are efficient, exhaustive in scope, and result in potential project cost savings that far exceed the cost of the survey itself.
Examples of GPR and ERI Images
Below are two examples of GPR data that illustrate how these data image utility pipes. The upper image shows two intersecting radar profiles. The positions, composition, and often condition of utility pipes (in colors) can be interpreted from these images as shown. The lower image is a map of GPR data only that shows the locations and depths of utility pipes as white lines.
The example ERI profile provided below shows what electrical resistivity data look like and their value in differentiating substrate conditions.