Aiming at evaluating the effects of vibration history on dynamic characteristics of normally consolidated clay

a series of multi-cycled cyclic shear tests were conducted on 16 soil samples under consolidation pressure of 50 kPa

100 kPa

300 kPa and 500 kPa respectively. The experimental results reveal that

on the stage of drainage and consolidation

with the development of duration shear modulus curve ascends while damping curve descends; this trend became significant as consolidation pressure increased. The variation tends to be stable in 25 hours. When subjected to cyclic loading controlled by constant strain amplitude

both the modulus and damping of soil samples change significantly during the first 50 cycles

and then the differences become moderate afterwards

in which the damping curve acts in hyperbolical type. It is also found that there exists a clear sign of pre-straining that affects damping more significantly than modulus.