Countermeasure for Reducing Micro-pressure Waves by Spreading Ballast on the Slab-track in the Tunnel

Impulsive pressure waves (micro-pressure waves) emitted from tunnel portals are one of the environmental problems affecting high-speed railways. The magnitude of the micro-pressure waves emitted from long ballast track tunnels decreases more than those emitted from long slab track tunnels due to the distortion of compression waves propagating through tunnels.