Geotechnical Engineering: Optimum moisture content for compaction of in situ soil at a residential construction site on Five Mile Prairie, WA.

Natasha Garland Clark, Eastern Washington University
Carly Sorensen, Eastern Washington University
Camie Bearup, Eastern Washington University

Abstract

The residential construction site is located at 9117 Scarlet Sky Drive on the southwest margin of Five Mile Prairie, WA. The footprint of the proposed structure overlaps two soils. Near the road is fill material brought in to form the extended roadbed. Further from the access road is the extant soil that formed in place on the prairie. This site is approximately 2,400 feet in elevation, atop basalt. Over time loess and the Glacial Lake Missoula floods shaped the landscape. Grassy, small rolling hills cover the in-situ soil. There is a natural drainage basin below the site that features basalt boulders rimming the edge as a result of many years’ past mass wasting. This study presents results for moisture content and compaction of in-situ soil according to ASTM Standard D698. Compaction prior to construction increases unit weight and shear strength for soil, hence increasing resistance to settling and structural damage.