A new report has been published by the Transport Research Laboratory concerning technologies for continuously monitoring the performance of "non-pressurised tubular structures": in particular, surface water highway drainage systems. The research was carried out by Messrs Harrington and Iaquinta for the laboratory, which provides expert witness services in all areas of transport and in particular road traffic incidents.
In an introduction to the report, Integrated monitoring system for drains and other tubular structures, the TRL says: "Failures on the motorway and trunk road networks often resulting from heavy rainfall occur because drains are not able to cope with the large volume of water they suddenly have to evacuate. Currently the assessment of these drains is carried out every 10 years using visual (closed circuit television - CCTV) or manual (mandrel) techniques to identify structural failures, with additional reactive assessments undertaken if issues (blockages or build-up of debris) requiring immediate treatment arise.
"It is thought that the routine assessments aimed at identifying structural failures will always be necessary to some extent; however the reactive approach to dealing with emergencies is less than ideal. Hence, there is a potential need for continuous monitoring that would be able to provide real-time or near real-time information about the state of a drainage network. Research was therefore carried out into a drain condition monitoring system which could be permanently installed and left in operation unattended."
The report deals with different methodologies for monitoring what is happening inside surface water drains, concluding with recommendations for two methods – radio wave attenuation and an acoustic-based approach – recommended for further trials. The authors then suggest other areas in which the techniques could be applied, in particular the monitoring of railway tunnels.
"...a similar approach could be implemented for much larger tubular structures, in particular to detect changes from a reference state. This would typically be the case for instance in underground obstacle detection systems (eg Unattended Train Operation) for monitoring tunnels and detect people or objects on the tracks. One of the advantages of this approach, compared to radar or video, is that there is no requirement for line of sight (ie it works the same if the tube is curved) with the ability to see beyond tunnel bends and corners."
The research followed on from a report published in 2010 by the same authors into Non-invasive techniques to assess drains.
The new report, reference PPR630; ISBN 978-1-908855-26-8; ISSN 0968-4093, can be downloaded from the TRL website, at www.trl.co.uk/online_store/reports_publications/latest_publications/.