On the influence of a non-cohesive fines content on small strain stiffness, modulus degradation and damping of quartz sand.

The influence of a non-cohesive fines content on small-strain shear modulus G max , small-strain constrained elastic modulus M max , shear modulus degradation G ( γ ) / G max , damping ratio D ( γ ) and threshold shear strain amplitudes γ tl and γ tv has been studied in approx. 130 resonant column (RC) tests with additional P-wave measurements by means of piezoelectric elements. Specially mixed continuous grain size distribution curves of a quartz sand with varying fines contents ( 0 ≤ FC ≤ 20 % , defined as the mass percentage of grains with size d < 0.063 mm according to DIN standard code) and uniformity coefficients ( 1.5 ≤ C u ≤ 50 ) have been tested at different relative densities and pressures. A significant decrease of G max and M max with increasing fines content was observed, while the modulus degradation curves G ( γ ) / G max were found rather independent of FC . A pressure-dependent decrease of the damping ratio and a slight increase of the threshold shear strain amplitudes γ tl and γ tv with fines content were measured. Extensions of several empirical equations for G max , M max , G ( γ ) / G max and D ( γ ) considering the influence of the fines content are proposed in the paper. [ABSTRACT FROM AUTHOR]