Evaluation of dynamic cone penetration test for liquefaction assessment of gravels from case histories in Italy

In North American practice, the Becker Penetration Test (BPT) has become the primary field test used to evaluate liquefaction resistance of gravelly soils. However, this test is expensive and uncertainties exist regarding correlations and corrections. As an alternative, the 74 mm diameter dynamic cone penetration test (DPT) developed in China has recently been correlated with liquefaction resistance based on field performance data from the Mw7.9 Wenchuan earthquake. In this study, liquefaction resistance was evaluated using DPT soundings with two hammer energies at two sites in Avasinis, Italy where gravelly soil liquefied in the 1976 Friuli, Italy earthquake. Gravel content ranged from 20 to 40% based on the 4.75mm criteria and The DPT liquefaction correlation correctly predicted liquefaction in all cases where liquefaction features were observed. These results indicate that the DPT can provide accurate liquefaction hazard evaluations for gravelly soils more economically than alternative procedures. Standard SPT energy corrections were found to be reasonable for the DPT.