Revealing the hidden: Dr Nicole Metje on the Underground Assets Challenge
Today we have a guest blog post on the Geovation Underground Assets Challenge. Dr Nicole Metje is a Reader in Infrastructure Monitoring at the University of Birmingham and Deep Dig Contributer. Her research focuses on mapping of buried utilities through surface geophysics and determining the causes and costs of utility strikes. Dr George Tuckwell is the director responsible for geosciences and engineering services within the RSK Group, he provides expert advice to clients on the use of geophysical technologies for mapping the subsurface.
Let’s see why why the Geovation Underground Assets Challenge is important…
Any work in the ground – building, installing new infrastructure or repairing existing assets – involves risk. The risk comes from lack of information, or having the right information but not acting on it correctly. If risks are realised, they can manifest as serious accidents and injury. They can also be expensive and disruptive. Avoiding risks means knowing as much as you can about the subsurface, imagine information as being the opposite of risk, and then using that information to create a safe system of work that delivers the project safely, on time and on budget.
If we take buried services as an example, there are procedures to map these thoroughly and documents that provide guidance on how to map these, present the data, and act on it to stay safe; nevertheless incidents and accidents continue to occur. There is a vast network of pipes and cables buried in the first few metres below the ground surface housing and transporting vital commodities such as water, gas, electricity and broadband. Whenever excavating, it is vital to know the location of these buried assets in order to minimize the risk of any excavation to the operator and the public, and cause significant economic impact due to project delays caused by inaccurate or incomplete knowledge of what lies beneath the street. Historic, statutory utility records provide an indication of what is buried in the ground and its location. However, many of these records are inaccurate or incomplete as many assets have been in the ground for 10s of years and longer and as-built information is not always recorded. Detection of these buried assets is normally through the use of geophysical technologies sending an active signal through the ground and recording the reflection. To date though, no individual sensing technology exists which can detect all buried assets in all ground conditions.
The Mapping the Underworld initiative brought together academia and industry to develop a multi-sensor device to locate buried assets, provide intelligence of the effects of the ground, use different data sources to reduce the risk of excavation and increase the use of the subsurface. In parallel, industry lobbied to develop an industry standard for the detection of buried utilities and ‘PAS 128: Specification for underground utility detection, verification and location’ was launched in 2014. This specification has made a significant difference to industry as it has created a level playing field for the industry to tender against and provided clients with a much better understanding of the different types of ‘utility survey’ available together with the achievable horizontal and vertical accuracies. The success of PAS128 was confirmed by Andy Rhoades from Heathrow airport stating that in just over 1 year Heathrow Airport detected triple the amount of underground utilities than had previously been mapped within the same areas despite having excellent information from before, check out this pdf.
Despite this fantastic progress, challenges remain with inaccurate location of buried assets and existing geophysical technologies have their limitations. Thus more work is required in this area to make every excavation safe and significantly reduce the number of utility strikes and their direct and indirect impacts. Buried services are one example, but relic mine working, old basements and foundations, contaminated land, buried waste and natural geological hazards are all sources of risk to the construction industry. There is enormous scope for Geo applications to support the acquisition, delivery, and use of information about subsurface risk, and to support the use of that information in safe digging and construction. That is why this Geovation initiative is so exciting.
Find out more about the Geovation Underground Assets Challenge here.