VICKSBURG, Miss. --
The US Army Engineer Research and Development Center has published the report/note described and linked below. Approved for public release: distribution is unlimited.
Geophysical Investigation at Eielson Air Force Base, Alaska: Subsurface Features Influencing Building 6385
Garrett Speeter, Kevin Bjella, Stephanie Saari, and Jon Maakestad
The U.S. Army Cold Regions Research and Engineering Laboratory conducted geophysical research of subgrade conditions to aid foundation design and to address differential settlement of Building 6385 on Eielson Airforce Base, Alaska. The study used electrical resistivity tomography and data from subsurface borings to characterize subsurface geologic units. Bedrock present beneath the building at a depth of approximately 80–105 ft has an approximate east–west strike and shallow dip to the northwest. Geophysical data indicates that frozen conditions beneath the site are a patchwork of thawed and thawing permafrost that is generally ice-poor with sporadic perched water on top of localized degrading ice-rich permafrost. Frozen soil beneath Building 6385 is thawing at a rate of at least 0.81 ft/year and has reached depths up to 80 ft. Advanced permafrost degradation is present beneath Quarry Road at the toe of the embankment slope for Building 6385. Permafrost beneath the north and northwest sides is more degraded and has more localized ice-rich soil. Fill on the west side of the building is thicker, suggesting more settlement has taken place. Permafrost degradation may have destabilized the tow of the embankment slope and contributed to settlement at the north edge of building.
47 pgs / 6.15 MB
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Release no. 19-006