Summary of Current Practice in Vibration Monitoring of Utility Tunnels and Shafts in the UK

Abstract

The development of urbanzation areas requires more land and space in the already congested space. Increasingly new structures are having to be constructed in proximity to existing underground infrastructure. In the UK, this infrastructure is of varying ages and the new construction poses a potential threat to the serviceability or integrity of existing structures in respect of their original SLS and ULS design capacities.

One of the concerns is construction vibration. Activities such as piling, demolition and compaction will generate vibrations at various frequencies. Due to the complexity of vibration propagation related to the structure damage, there is a lack of reliable data on the threshold of vibration-induced damage in structures both in countries where national standards already exist and in the UK. This paper will summarize the currently available UK guidance, BS 5228-2, BS 7385-2, and CIRIA TN142, build up a systematic assessment approach, and present real monitoring data collected from construction sites. These monitoring data are normally enormous and recorded in real time, hence opened the opportunities for artificial intelligence data transmission and alert notification.

The assessment approach suggested to adopt the 3 Tiers system similar to the better developed building response to ground movements assessment proposed by Burland (1995) and Mair (1996). The first tier will screen out any structures monitored to have less than a threshold of vibration because damage to these structures is highly unlikely. The second tier will look at individual sources of vibration frequency, if applicable, and their respective limits will be assigned according to available case histories. The third tier will apply if monitored vibrations at a particular structure exceeds the limits set out in the second tier. A detailed inspection and specific structure assessment will be required to ensure the integrity of such a structure. The artificial intelligence driven monitoring can apply this criterion accordingly.