Wang Zhihua

DYNAMIC MODULUS AND DAMPING RATIO OF EPS COMPOSITE SOIL UNDER SMALL STRAIN CONDITION

Abstract: Dynamic shear modulus and damping ratio are important parameters to evaluate mechanical properties of soils. Expanded polystyrene (EPS) composite soil is mixed with EPS beads, cement, soil and water, which is usually used as a filling material in Road Engineering, Civil Engineering and so on. A series of resonant column tests were carried out to study the effect of EPS beads content, cement content and confining pressure on the dynamic modulus and damping ratio of EPS composite soil under small strain condition. Testing results show that the effect of cement content on the dynamic shear modulus is the most significant followed by EPS beads content, while the confining pressure has a slight effect. The initial shear modulus of EPS composite soil increases linearly with the confining pressure, while EPS beads impact on the initial shear modulus associated with cement content. The normalized shear modulus of EPS composite soil is less affect by EPS beads, while it is significantly influenced by cement content and confining pressure. The attenuation characteristic of normalized shear modulus for EPS composite soil can be well fitted by Davidenkov model. The damping ratio of EPS composite soil increases with cement content, while confining pressure has a slight effect on the damping ratio. The influence of EPS beads content on the damping ratio is more complicated due to the uncertainty of weak interface between EPS beads and soil particle. This study can provide references for the design and application of EPS composite soil in practical engineering.