ANN FOR CORRELATION BETWEEN SHEAR WAVE VELOCITY OF SOIL AND SOME GEOTECHNICAL PARAMETERS

Shear wave velocity (Vs) is known as one of the fundamental material parameters which is useful in dynamic analysis. It is especially used to determine the dynamic shear modulus of the soil layers. Nowadays, several empirical equations have been presented to estimate the shear wave velocity based on the results from Standard Penetration Test (SPT) and soil type. Most of these equations result in different estimation of Vs for the same soils. In some cases a divergence of up to ۱۰۰% has been reported. In the following study, having used the field study results of Urmia City and Artificial Neural Networks, a new correlation between Vs and several simple geotechnical parameters (i.e. Modified SPT value number (N۶۰), Effective overburden stress, percentage of passing from Sieve #۲۰۰ (Fc), plastic modulus (PI) and mean grain size (d۵۰)) is presented. Using sensitivity analysis it is been shown that the effect of PI in Vs prediction is more than that of N۶۰ in over consolidated clays. It is also observed that Fc has a high influence on evaluation of shear wave velocity of silty soils.