Based on amount of freeze-thaw tests and dynamic triaxial tests

the dynamic modulus and damping ratio properties of silty soil subjected to repeated freeze-thaw cycles were deeply researched and analyzed. The tests results are drawn as follows: At the same dynamic strain level

the relationships of dynamic stress and freeze-thaw cycles

water content present negative correlation

and the relationships of dynamic stress and confining pressure

frequency

compactness present positive correlation. The curves of dynamic stress vs. dynamic strain obviously present nonlinear relationship; and the dynamic modulus double decreases while the damping ratio double increases with the increasing of dynamic strain. The dynamic modulus sharply decreases while the damping ratio increases with the increasing of freeze-thaw cycles; and then the changes level off after 6 freeze-thaw cycles; while the mechanical properties after 6 freeze-thaw cycles are suggested for designing and calculating indexes. The soil particles contact area is improved by the increasing of confining pressure and compactness; and the dynamic modulus increases while the damping ratio decreases with the increasing of confining pressure and compactness. It is found that water content less affects damping ratio

but the dynamic modulus double decreases when the silty soil reaches saturation condition. The frequency is an important factor affecting on damping ratio

and damping ratio sharply decreases as the frequency increases.