High Speed 1 - Tunnel Ventilation Shafts

Southdowns were commissioned to investigate the noise emissions from the CTRL ventilation shaft headhouse buildings as part of the commissioning of the railway during controlled Eurostar movements at service speeds.

Extensive digital acquisition of noise signals was undertaken at each of the sites across London to enable an appreciation of noise generated by both mechanical equipment, and passing trains in the tunnels, with the latter also giving rise to regenerated noise from air flow within the shafts.

Data was used to identify relative contributions and to assess compliance with the Projects noise commitments, requiring the emissions not to exceed 5 dB over the pre-determined background noise level at sensitive receivers.