| Lightweight clay-EPS beads soil (LCES) is a new geotechnical material, which is light in self-weight, high in strength and therefore has the capacity of self-standing. Besides the adoption of LCES reduces construction time and minimizes the pollution to environment, so LCES has extensive prospect of application in geotechnical engineering. In this paper, the LCES was prepared by treating mucky clay with EPS beads and cement, and a series of laboratory dynamic triaxial tests were carried out to study the dynamic properties of LCES, the main contents and conclusions of the study are described as follows:(1) Based on the dynamic triaxial tests, the dynamic deformation properties of LCES are studied, the effort is focused on the influence of confining pressure, cement content, EPS content, curing ages and cyclic loading frequency. The results indicate that its dynamic stress-strain curve is hyperbolic type. The dynamic strain (εd) of LCES decreases with increasing confining pressure, cement content, curing ages and cyclic loading frequency when it is subjected to the same dynamic stress (σd). At the same dynamic strain, the dynamic secant elastic modulus (Esec) of LCES increases and the damping ratio(D) decreases with increasing confining pressure, cement content, curing ages and cyclic loading frequency. The curves ofσd～εd,Esec～εd and D～εd with different EPS content intersect respectively, the trend of LCES deformation characteristic is inversely proportional to EPS content near the intersection. The value of dynamic strain at the intersection is about 0．5%3．0%, the magnitude of which is related to the mixing proportions and confining pressure. Compared with the confining pressure, cement content and curing ages, the EPS content and cyclic loading frequency have little effect on the dynamic deformation of LCES.(2) Based on the properties of the stress-strain curves of LCES, the maximum dynamic shear modulus (Gmax) of LCES in various mixing proportions is obtained. Considering synthetically the influences of confining pressure, cement content, EPS content, curing ages and cyclic loading frequency, the empirical formula of Gmax and Dmax are obtained by statistical regression analyzing on the test results.(3) Based on the dynamic triaxial tests, the dynamic strength properties of LCES are studied, the effort is focused on the influence of confining pressure, cement content, EPS content, curing ages and cyclic loading frequency. Firstly, the material will be in failure when the compressive strain reaches 5%, which can be considered to be a suitable dynamic failure criterion of LCES, and then the effort is focused on the confining pressure, cement content and EPS content effect on the dynamic strength properties of LCES. The test results indicate that the dynamic strength of LCES increases with the increasing confining pressure, cement content, curing ages and cyclic loading frequency, but the effect of confining pressure on the dynamic strength declines when the cement content increases. The dynamic strength of LCES initially increases and then decreases with the increase of EPS content, so LCES may has an optimal EPS content for the dynamic strength.(4) With increasing of cement content, the Mohr circle's diameter of LCES increases and exceeds the origin. Based on the dynamic strength envelope, the dynamic parameter, Cd and (?)d, of LCES is obtained. The empirical formula between dynamic shear strength and failure cyclic number is obtained based on the dynamic strength test results, and then the dynamic shear strength curves of LCES are normalized.(5) Based on the Hardin-Drnevich constitutive model, an improved constitutive model is introduced, which is taking into the consideration of special structural properties of LCES by using correction coefficient k. The method of deducing the correction coefficient was discussed in detail. The validation shows that the basic dynamic deformation rule of LCES can be reflected by the improved model.
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