Liquefaction subsurface investigation for Milford Dam

The US Army Corps of Engineers (USACE) completed a liquefaction potential analysis as part of the seismic evaluation of Milford Dam in 1986. This paper uses data from the 1986 study to compare fines content data from in situ frozen and standard penetration test (SPT) samples that suggest fines content can be overestimated by 1–10% by SPT samples in stratified sand deposits. This result may have implications for liquefaction assessments because split-spoon samples may overestimate the actual fines content, resulting in a liquefiable deposit being classified as nonliquefiable. In addition, the paper evaluates the effectiveness of ground freezing on maintaining in situ soil structure and aging of the foundation sands at Milford Dam.