Adjusting a power sub-station expansion to the environmental circumstances
The “as-builts”, submitted by the contractors, not only showed a high voltage (230 KV) line emanating directly from the building – it was also cooled with a dielectric fluid containing hazardous materials.
A geotechnical firm was brought in to perform borings. To avoid causing damage to any buried utilities they had to begin by scanning the ground to collect vital information about the subsurface. Since EM, the conventional method for ground scanning, was rendered ineffective, the solution was to use Ground penetrating radar.
Data was collected from a prescribed grid, that covered the entire area. A line, 45 degrees from the building, could be designated and a geotechnical boring stake was placed exactly over the line. A vacuum excavation was also performed during the construction, from which they could confirm the accuracy of the collected GPR data.