Acoustic Performance of Asphalt Concrete Underlayment for High-Speed Railway Substructures

To compare the rail noise levels with different substructures, a sound-solid coupling model was established using FEM-based ABAQUS software to simulate noise changes in the sound field generated from structural vibration. Sound pressure values were selected from the sound field and transformed to sound pressure levels for quantitative evaluation of noise levels of two asphalt concrete underlayments (ACRS-1 type and ACRS-2 type) and an ordinary slab track structure. The results show that the sound-solid coupling model can successfully evaluate different rail noise levels. Comparison of the above three kinds of track infrastructures indicates that the noise levels of the ACRS-1 and ACRS-2 type structures are generally lower than that of the slab track structure; especially, the noise level of the ACRS-2 structure is lower than the noise levels of the other two structures. Moreover, noise reduction amplitude occurs in 0.01 s, 0.02 s and near 0.03 s, particularly in the vicinity of 0.02 s. The noise amplitude of the ACRS-2 type structure is 10-20 dB lower than the ordinary slab track structure, whereas the noise amplitude of the ACRS-1 type structure is 5 dB lower than that of the ordinary slab track structure.