Degradation of dynamic elastic modulus of soft clay under cyclic loading

A series of undrained cyclic triaxial tests were performed on typical Hangzhou soft clay under cyclic loading.The effects of initial deviator stress,loading frequency,overconsolidation ratio,and cyclic stress ratio on dynamic elastic modulus were investigated.The results showed that the dynamic elastic moduli decrease with the increase of strain under different load frequencies.However,the change of the frequency has little effect on the degradation of dynamic elastic modulus.The effect of initial deviator stress is significant.With the increase of initial deviator stress,the dynamic elastic modulus increases greatly under the same level of dynamic strain.Clay with a high the overconsolidation ratio has high strength and does not degrade easily.But when the overconsolidation ratio is low,the dynamic elastic modulus degrades greatly.Finally,an empirical equation for the relationship between degradation of dynamic modulus and strain was proposed by the regression analysis method.