At present

the experimental research on the dynamic deformation behavior of EPS composite soil is restricted to the conventional dynamic triaxial shear test.The complex initial stress conditions and stress paths induced by the earthquake

wave and traffic loadings can not be considered because of the poor instrument conditions.Aiming at this issue

the dynamic deformation behavior of EPS bead composite soil subjected to the traffic loading was studied in consideration of complex initial stress conditions through the GDS hollow cylinder torsional shear apparatus.The influences of the following five factors on the dynamic modulus and damping ratio of EPS bead composite soil were analyzed.The factors are volume ratio of EPS beads to the soil Ve/Vs

initial average effective consolidation pressure p0

initial consolidation stress ratio R0

initial intermediate principal stress coefficient b0

and initial principal stress direction angleα0.The results indicate that the relationship between Ve/Vsand the dynamic deformation properties of the test soil is affected by the p0.The dynamic modulus of the test soil increase with Tncrease of R0 when it was subjected to the same dynamic strain

but R0 had a slight influence on the damping ratio of it.Compared with theα0and b0

the p0 has a greater effect on the dynamic deformation properties of the test soil.