Gravel Liquefaction Assessment Using the Dynamic Cone Penetration Test Based on Field Performance from the 1976 Friuli Earthquake

The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance of gravelly soils based on field performance data from the Mw7.9 Wenchuan earthquake. With a diameter of 74 mm, DPT would be less sensitive to gravel size particles than the SPT or CPT and could be a viable assessment tool depending on gravel size and percentage. In this study, liquefaction resistance is evaluated using four DPT soundings with two hammer energies and shear wave velocity (VS) measurements in Avasinis, Italy, where gravelly sand liquefied in the 1976 Friuli, Italy, earthquake. The DPT correctly predicted liquefaction at three sites where liquefaction was observed; however, it also predicted liquefaction in a highly stratified silt and silty gravel profile where ejecta was not observed. This failure appears to be a result of the "system response" of the profile, which impeded ejecta as identified at similar stratified sites in New Zealand. VS1-based triggering curves often predicted no liquefaction at sites where liquefaction was observed, suggesting that the boundary curves may need to shift to the right for gravelly soils. Standard SPT energy corrections were found to be reasonable for the DPT.