Shear modulus from SPT N-values with different energy values

Abstract It is essential to determine low strain shear modulus ( G m a x ) to model dynamic soil response and estimate the site effects due to earthquakes. Several correlations have been developed between dynamic soil properties and soil penetration resistance values such as N-values from Standard Penetration Test (SPT). However, only a few of the established correlations are often used because of uncertainty over applied hammer energy ( E H ) and applicability in different regions. Hence, this study aims to signify the importance of E H in N-value corrections, its influence on G m a x estimation, to suggest modification factor for an existing correlation and validate with Downhole and Crosshole measurements. Different SPT corrections are studied besides the energy measurements in the analysis of the correlation between the N-value and G m a x . A previously proposed correlation between measured N-value and G m a x is improved to account for in-situ E H measurement, and the correction factors to account for different hammer energy ratios (ER) are suggested. Modified correlations compared well and agreed within the 95 % confidence bound with the freshly acquired seismic borehole tests data.