Laboratory tests, using the resonant column method, were conducted to evaluate the dynamic properties of compacted silty clay under one dimensional condition. The variables considered were the initially applied static load, the vibration amplitude, the water content and the height-diameter ratio.
　The water content was found to affect appreciably the values of wave velocity and constrained modulus, but its influence on the dampign ratio was small. Although the effect of stress conditions on the dynamic properties of soils was less significant　compared with that of water content, the trend toward the Sshaped stress strain characteristics was observed.
　Wave velocities or constrained moduli could be uniquely determined independently of height-diameter ratio, while the dissipative parameters are dependent on the height-diameter ratio. From this observation, the validity of the assumed mechanical model was discussed.