Vibration and noise is harmful to human health and buildings. The longer a man is exposed to vibration and noise, the greater the risk of health effects and mental suffering.The longer a building is exposed to vibration and noise, the greater the risk of structure effects and mechanical disorders.
The travelling-through-town metro lines transmit huge vibration and noise. So the metro track, which travels at the side of large quarter, hospital, school and important buildings, must be treated to lower its vibration and noise level.
The unit ‘dB’ is used to evaluate vibration and noise reduction effects. 1dB might be seen as that, the after vibration is 1/10 of the former. 1dB(A) might be seen as that, the after noise is 1/10 of the former.
By how many dB should the track noise be reduced? In China, the technician compares the previous vibration and noise level plus experiences data and Chinese standard. And then the value to be decreased comes out.
Using a high buried depth of track, elastic fastening system or elastic under slab mat can make it work. But how to choose this extra cost from a third of a million to several million US dollars? It depends on the ‘dB’ you want.
- No need to do vibration reduction treatment section: normal fastener. More than five Chinese companies can do this and the price is about $32 per set
- 3dB-8dB: in the past, the Chinese metro line used Cologne eggs, but after the Sunrui GJ-III was pushed into the market, most of them changed to GJ-III. GJ-III has more adaptability to gauge / height adjustment and the vibration effect is better. Nowadays, the total laying length for the GJ-III fastener in China is over 400km and is still increasing
- 10dB-15dB: elastic anti-vibration slab mat or Vanguard fastener. If the line is not jet-built, laying the anti-vibration slab mat is the most easy way. It’s convenient to install and structure-safe. Operated line should use Vanguard fastener. The Sunrui GJ-IV ‘floating fastener’ is more apposite. The rail doesn’t touch the bottom of the fastener and is set up by rubber block
- 15dB-20dB: Steel-spring Floating Slab or combination use of the Sunrui anti-vibration slab mat and GJ-IV fastener.Steel-spring Floating Slab is strong and reliable, but can’t be changed in three hours when the broken day arrives. Combination slab track is able to change in a short time and the vibration reduction effect for the two are the same