Dynamic modulus and damping ratio of compacted loess under long-term traffic loading

Previous studies have centred on the long-term permanent deformation behaviour of soil under traffic loading while neglecting the dynamic parameters as it is affected by cycle number. In this study, forty tri-axial dynamic tests were conducted to assess the effects of cycle number, confining pressure, and dynamic stress on the dynamic modulus and damping ratio of compacted loess. Empirical models of both parameters were established and examined, from which emerged a nearly linear relationship between the dynamic stress-strain points when dynamic stress fell below a given threshold value. The representative dynamic modulus in the linear range initially increased and then decreased. The maximum representative dynamic modulus linearly increased as confining pressure increased, while confining pressure had no clear effect on the damping ratio. As the dynamic stress increased, the damping ratio was initially stable and then gradually increased until becoming stable again at a higher level.