Empirical shear wave velocity equations in terms of characteristic soil indexes

Abstract

AbstractAn investigation to systematize empirical equations for the shear wave velocity of soils was made in terms of four characteristic indexes. The adopted indexes are the N‐value of the Standard Penetration Test, depth where the soil is situated, geological epoch and soil type. As some of these indexes are variates belonging to interval scales while others belong to nominal or ordinal scales, the technique known as a multivariate analysis cannot be employed. A new approach to the theory of quantification, after C. Hayashi, was introduced and developed for solving this difficulty.Fifteen sets of empirical equations to estimate low strain shear wave velocity theoretically may be obtained by combining the above four indexes. All of these sets were derived by use of about 300 data, and their accuracies were evaluated by means of correlation coefficients between the measured and estimated shear wave velocities. The best equation was found to be the one which included all the indexes, and its correlation coefficient was 0.86. The empirical equation relating the standard penetration N‐value to the shear wave velocity provided a correlation of only 0.72, and is one of the lowest ranking among the 15 sets of equations.