New statistical and graphical assessment of CPT-based empirical correlations for the shear wave velocity of soils

The object of this paper is to gather, analyze and assess CPT-Vs correlation equations. Consequently, in this paper the validity of some of these correlations between Vs and CPT parameters for Jiangsu clays was assessed using piezocone data from Yangtze Delta deposits through six existing and two new indexes and the cumulative frequency curve graph. Common existing correlations are briefly reviewed and discussed. New empirical formulae are suggested to correlate CPT-based parameters and Vs, using regression analysis. The comparison is conducted between the existing and proposed equation based on a dataset collected at seven sites in Jiangsu, China. This paper proposes a new statistical assessment method taking the location of the points into account, including the perfect distance and the slope of the specific line that links the point D10 and the point D90. The method is more obvious and accurate. The results of these indexes and the cumulative frequency curve graph show that a new improved expression gave better performance. The new indexes and the cumulative frequency curve graph can surely be used to analyze and assess correlations including the new expression, which is very helpful to evaluate correlations.