Evaluation of Shear Wave Velocity Based on the Standard Penetration Test (SPT)

Shear wave velocity (VS) is an important engineering property that is used for evaluating the soilshear modulus as well as defining the soil type in pseudo-static analysis. In this paper, acorrelation between VS and corrected SPT blow counts (N1,60), and depth (Z) is developed. A newpolynomial model is proposed to correlate the mentioned parameters and VS, predicated on a totalof 127 data sets, including field investigation records from three sites in the southern and easternparts of Iran. This study addresses the question of whether a new polynomial model could be usedto estimate VS based on the specified variables. Furthermore, inaccuracies in the measurement orestimation of the influencing parameters have always been a major concern in the prediction offuture earthquake ground motions. In this article, based on robust optimization, an innovativeapproach has been utilized to evaluate the effect of such uncertainties. The results show thatcompared to the previous statistical relations, the new polynomial model provides a moreeffective means for recognizing the patterns in the data and accurately predicting the VS. Thesensitivity analysis reveals the influence of the involved parameters. It is shown that the newpolynomial model performs better in deterministic evaluation taking into consideration theuncertainties.

Keywords:

Shear Wave Velocity , Standard Penetration Test , Polynomial , Uncertainties , Robust Optimization