J02a RB Geotech Report from 300 feet away.pdf

This is a Site Exploration and Geotechnical Engineering Report for a proposed Tracker Mounted Array solar panel installation at the Indian Health Services Hospital in Rosebud, South Dakota. The report was prepared by Twin Rivers Testing & Environmental, LLC and submitted to Chris O'Bryan at LaCreek Development on October 20, 2014.

The exploration involved two soil test borings drilled to 15 feet below ground surface to characterize subsurface conditions for helical pile foundation design. The site soils consist of Sandy Lean Clay, Clayey Sand, and Poorly Graded Sand with Clay, which are suitable for the proposed 10-foot-deep helical anchor installations supporting twelve solar panel tracker units in a 154 ft. by 219 ft. area. Recommended lateral bearing pressures are 180 PSF for Sandy Lean Clay (with a note that it should be neglected due to frost action) and 250 PSF for Clayey Sand and Poorly Graded Sand. The report includes detailed geotechnical recommendations for site preparation, fill placement and compaction requirements, excavation and utility trenching procedures in accordance with OSHA standards, seismic design considerations (Site Class "D"), and drainage provisions to prevent water accumulation. No groundwater was encountered during drilling, though the report notes that groundwater levels may fluctuate seasonally. The appendices contain boring logs, a boring location map, keys to symbols, and definitions of geotechnical terms.