Abstract：A 3D computer simulation method for rectangular-section tunnel was presented to calculate traffic noise inside and outside of tunnel. This method was composed of microscopic traffic simulation technology, traffic noise emission model and sound propagation model. Particularly, 20 times of reflections were taken into consideration by using Image Source method, and a diffraction of direct sound and reflected sound was simulated outside tunnel. The results show that, the increment of pressure level is not related to the change of traffic volume; it reduces significantly as the absorption coefficient of tunnels increases.
2012, Vol. 31 
