Group AB filler is an important part of high-speed railway subgrade bed packing.The dynamic deformation characteristics have important roles for the normal operation of the highspeed railway.Based on high-speed railway subgrade bed working conditions

the confining pressure which ranging from 10 kPa to 150 kPa and loading frequency which ranging from 1Hz to 5Hz were deduced in dynamic triaxial tests.On the basis of this study

the dynamic elastic modulus of high-speed railway subgrade group AB filler was studied.The influences of confining pressure

compaction and loading frequency on dynamic elastic modulus were analyzed under the train loading.The experimental results show that relationship between dynamic stress and dynamic strain of group AB filler has obvious nonlinear and strain softening characteristics

and the reciprocal of dynamic elastic modulus and dynamic strain curve shows a linear relationship

indicating that the dynamic constitutive relations of group AB filler can be analyzed by Hardin hyperbolic model.Dynamic elastic modulus increases with the confining pressure increasing;and with the degree of compaction enhancing

dynamic elastic modulus increases nonlinearly

and the loading frequency has some influence on the dynamic elastic modulus.When the strain is less than0.05%

the influence of frequency on dynamic elastic modulus is greater.But when the strain is greater than 0.05%

the influence of frequency can be ignored.