Abstract : The shear-wave velocity (Vs) offers a means to determine soil's seismic resistance to liquefaction by a fundamental soil property. This talk will present the results of a twenty-five year-long international project to advance all principal field methods (CPT, SPT, Vs) to develop stand-alone and hybridized probabilistic correlations for seismic soil liquefaction triggering. Our first shear wave velocity correlation (2013) required a large field-testing campaign leveraged largely by literature-based CPT and SPT studies. The first correlation analyzed 121 sites from the literature and 310 new test sites investigated in China, Japan, Taiwan, Greece, and the United States.
We are updating that initial correlation and have expanded the data set to approximately 650 sites, mainly through new testing of sites from the M9.0 2011 Tohoku Earthquake in Japan and the 2011 Christchurch and 2010 Darfield Earthquakes in New Zealand. Of critical importance, these new case histories occupy locations previously investigated by CPT and SPT penetration testing. Bayesian regression and structural reliability methods facilitate a probabilistic treatment of the Vs catalog for performance-based engineering applications. Analysis of the mean and distributions (uncertainties) of all variables comprising seismic demand and soil capacity is integral to understanding overall model error.
Soil Liquefaction April 7, 2011, at Arahama, Watari, Japan, during an M7.4 aftershock from the Great East Japan M9 Earthquake of March 11, 2011.
Probabilistic correlations from field data for Vs, SPT, and CPT.