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| In-situ dynamic experimental study for simulating dynamic response of subgrades |
| LOU Shuang |
| (Department of Civil Engineering，Anhui Communications Vocational and Technical College，Hefei，Anhui 230000，China) |
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Abstract The dynamic response rule of subgrades under dynamic loads is the basis for studying the long term dynamic stability of the subgrades. The self-developed separated variable frequency vibration exciter was used to carry out full-scale model tests to study the railway subgrade dynamic response. The dynamic response rules of the railway subgrade under different excitation frequencies and dynamic load levels were studied. The test results show that the resonance frequency of the railway subgrade which was filled with lime improved soil and silty clay is 25 Hz and the vibration acceleration and dynamic stress of the subgrade surface increase significantly with increasing the excitation frequency. The vibration acceleration and dynamic stress along the depth and horizontal direction were researched. It is revealed that the vibration acceleration and dynamic stress in the depth of 1.5m reduce by 90%，which indicates that the vibration acceleration and dynamic stress along the depth attenuates faster than those of the ballastless track subgrade. The changes of the vibration acceleration and dynamic stress in the horizontal direction are affected by the stress diffusion effect. To be specific，the vibration acceleration and dynamic stress decay rapidly in the shallow horizontal plane while keep relatively stable in the depth of 0.7m. The research results reveal the spatial variation characteristics of the subgrade dynamic response.
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2020, Vol. 39 
