Gravel liquefaction assessment using dynamic cone penetration and shear wave velocity tests based on field performance from the 1964 Alaska earthquake

Abstract

Evaluating the liquefaction potential of gravelly soils using in-situ testing remains a challenge in geotechnical engineering practice. The Chinese Dynamic Cone Penetration (DPT) test provides an alternative for in-situ testing in gravelly soils to Becker Penetration Test (BPT) and the Standard Penetration test (SPT). The Chinese DPT was recently correlated with liquefaction resistance based on field performance data from the Mw 7.9 Wenchuan earthquake. In this study, liquefaction resistance was evaluated using the DPT and shear wave velocity measurements at eight sites in Seward and Old Valdez, Alaska, where gravel liquefaction took place and two sites in Valdez, where no liquefaction occurred in the 1964 Alaska earthquake. The DPT-based liquefaction triggering curve predicted liquefaction potential at all test sites with moderate accuracy. N′120 blow counts from SPT hammers were generally consistent with those from the DPT hammer after energy correction. Back-calculated energy correction factors were typically within 10% of the theoretical energy correction factor. These results suggest that the DPT can provide liquefaction hazard evaluations accurately and economically for many gravelly soils. Liquefaction evaluations using currently available Vs-based triggering curves developed for sands often indicated no liquefaction at sites where liquefaction occurred at the Alaska sites. In contrast, a Vs-based triggering curve developed from a data set of gravelly soil sites correctly predicted liquefaction at all sites.