Stiffness Degradation and Damping Ratio of Sand-Gravel Mixtures Under Saturated State

Abstract

The aim of this research was to explain the effects of gravel content using the intergrain state concept, relative density and confining pressure on G max, G/G max–γ and D–γ curves and the reference strain (γ r). A total of 45 G–γ and D–γ curves derived from resonant column testing and cyclic triaxial testing along with S-wave velocity measurements obtained using the bender element technique were assessed. The test specimens were prepared with different gravel contents (0, 30, 50, 75 and 100%) under different relative densities (10, 30 and 60%) and mean effective confining pressures (100, 300 and 600 kPa). Comparison of the G max results of the resonant column and bender element tests was also carried out. The desired excitation frequencies and ratios λ/D 50 and d/λ (where λ is wavelength, d is transmission path length and D 50 is average particle size) were determined based on the bender element tests results. The test results were used to evaluate the empirical equation for prediction of G max and to develop a new prediction equation with which to estimate γ r. The results of the tests were used to validate previous models and empirical curves.