Theoretical analysis on ground vibration attenuation using sub-track asphalt layer in high-speed rails

Abstract

Using a finite element method (FEM) program, a Portland cement concrete slab trackbed (S 0), and a sub-track asphalt roadbed (RAC-S) were modeled under high-speed train loads to analyze their responses to ground vibration attenuation, by considering 10, 15, 20, 25, and 30 thick sub-track asphalt layer replaced on the top of the upper subgrade. FEM results show that the vibration amplitude of RAC-S is at least three times lower than the vibration for S 0. The maximum vibration amplitude of RAC-S is linearly increased with train speed. The vertical acceleration is found to be reduced by more than 10 % when the asphalt layer thickness is increased from 10 to 20 cm. However, the reduction in vertical acceleration is only about 1 % when the thickness of the asphalt layer changes from 20 to 30 cm. The vibration level is slightly lower if the asphalt layer has higher resilient modulus in the seasons of autumn or winter. This theoretical analysis indicates that a railway substructure that consists of a 10–20 cm thick high modulus asphalt layer located at the top of trackbed shows a good performance in ground vibration control for high-speed rails.