Secant Young's modulus from N-value or Cu considering strain levels(1994)

H.Hirayama(GEO TOP)


It has been pointed out that deformation moduli based on conventional insitu and laboratory tests 'are generally too low to obtain appropriate deformations under design loads, and that shear moduli from seismic velocities Gd Should be used as upper bounds on static shear moduli. However, direct measurements of Gd are expensive and cumbersome. Then it is often required to evaluate Gd froln conventional tests in 'practice. Evaluation of Gd frouL SPT N-value or shear strength cu is discussed, and the following relationships are recomuended as average values: Gd=5N[MPa] or 500cu. Introducing Gd ,or Ed as the initial tangents of simple hyperbolic curves, strain-dependent moduli for linear or simplified non-linear analyses are evaluated. As an exalnple of application, pile settlement analysis with a simplified non-linear BEM. is shown.