Abstract:In order to research the dynamic property of the remoulded red clay under small shear strain amplitude condition,through imposing torsional vibration and changing the driving frequency step by step on the soil column with certain humidity, density and stress conditions, the resonant frequencies of the soil sample were measured.Then by cutting off the driving force, the vibration reduction curves were measured.The test can obtain the variation rules and influence factors of the dynamic shear modulus and damping ratio of the remoulded red clay under small strain condition. The results showed that the dynamic shear modulus of the remoulded red clay is relatively bigger, therefore its ability to resist deformation is relatively stronger. When the dynamic shear strain is small than 1×10^-4,the dynamic shear modulus reduce slowly, but when the dynamic shear strain is more than 1×10^-4, the dynamic shear modulus reduce rapidly.The damping ratio of the remoulded red clay is relatively smaller,so the stress wave can transfer faster and deeper in the soil and its energy reduction is slower.By using the improved Davidenkov model, the dynamic indexes of the remoulded red clay are fitted and the effect is pretty good.