A correlation to evaluate cyclic resistance from CPT applied to a case history

A methodology to evaluate the undrained cyclic resistance of sandy deposits from cone penetration tests through the state parameter is applied to the case history of the village of San Carlo (Italy), where widespread liquefaction phenomena occurred during the 2012 Emilia earthquake. The mechanical behaviour of the sand retrieved in the area of San Carlo was characterised within the framework of critical state soil mechanics via a series of monotonic and cyclic triaxial tests carried out on both undisturbed and reconstituted samples. Centrifuge cone penetration tests were also performed on reconstituted models of the same material. The results of centrifuge and undrained cyclic triaxial tests were interpreted through the state parameter to calibrate a direct correlation between the cone resistance, q c and the undrained cyclic resistance ratio (CRR). CRR profiles were deduced from the CPTs performed at sites in San Carlo where liquefaction took place using the correlation calibrated herein and a liquefaction assessment was carried out. The results of the proposed method was compared to a well-known simplified approach.