Estimating the undrained shear strength from SPT energy dynamics
DOI:
https://doi.org/10.24849/j.geot.2015.133.03Keywords:
Undrained shear strength, Statistical adjustment, SPT, Pile driving energy, Energy efficiencyAbstract
This paper aims at developing a method to estimate the undrained shear strength (Su) using an approach based on the concepts of wave propagation theory applied to the SPT. A database for clay deposits was developed and used to support the analysis and proposed formulation. The method combines the theory for energy conservation with limit equilibrium analysis applied to the static load capacity of an isolated pile. From this approach, values of Su are predicted as a function of the coefficient of adhesion α obtained directly from the measured NSPT blow count derived from statistical analysis. The proposed method gives estimates of Su in the range of measured field values, with a coefficient of correlation (r2) of 0.65%, which reflects the inherent scatter of SPT measurements.
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