A series of cyclic tri-axial shear tests were carried out on saturated sand by the soil static and dynamic hydraulic pressure triaxial and torsion multifunction shear apparatus.The influence degree of the vibration frequency on liquefaction strength value is studied.In the conditions of consolidation ratio at 1.0 and 1.5 and the vibration frequencies at 0.05

0.1 and 1.0 Hz

the liquefaction intension experiments were conducted on the dense sand of 70% relative density under 100

200

300 kPa confining pressures and the 28% loose sand under 100 kPa confining pressure.The experimental results show that the liquefaction strengths of the saturated dense and loose sand were increased with the increasing of vibration frequencies under different consolidation conditions.With the same destruction vibration frequency

all of the relations between the liquefaction strength and vibration frequency on log-log coordinates were linear.The change of liquefaction strength from 0.05 Hz to 1 Hz caused liquefaction strength changing over 25%.The dynamic strength index φdwas increased with the increasing of vibration frequencies

the maximum difference was 12.2%.The time of the sand destruction became shorter with the increasing of vibration frequencies.The influences of the vibration frequencies on loose sand were more obviously than dense sand.