comparison of shear wave velocity prediction models to yangtze river deltaic sediments based on piezocone test data

Seismic piezocone (scptu) data compiled from 37 sites in the southern yangtze delta, china, are used to evaluate several existing empirical correlations in predicting the shear wave velocity of deltaic sediments. four indices were employed in the assessment: the ratio of the estimated values to the measured vs values, the root-mean-square error, the ranking index, and the ranking distance. it is shown that all the considered prediction models are biased, generally over-estimating the observed shear wave velocity of the predominant intermediate soils in the yangtze delta. the results also reveal that the overall best correlation for the mixed deltaic soils is given by robertson [can geotech j 46(11):1337–1355, 2009]. it is hypothesized that the unique depositional environment of the considered soils is the primary source of the observed prediction bias. further statistical analysis indicates that partial drainage effects during cone penetration in deltaic intermediate sediments should be taken into careful consideration to derive reliable vs values from cptu data when applying correlations from the literature. more suitable site-specific shear wave velocity prediction correlations should be introduced, according to the recent findings on the yangtze delta scptu database.