Discover the future of earthworks monitoring via ICE WebEx
PRIME presentation is available to ICE members
At the end of last year, ITM Monitoring – a SOCOTEC Company – held an exclusive event at the Institution of Civil Engineers to showcase an innovative new earthworks monitoring technology, PRIME. This technology allows asset owners to ‘see inside’ vulnerable earthworks using a cost-effective, non-invasive system, providing early warnings of asset deterioration.
If you were unable to attend the event in person, but would like to watch the presentation in full, a WebEx is available to ICE members via this link. Or, for an overview of the new technology and the event, read on…
What is PRIME?
PRIME was developed by the British Geological Survey (BGS) Geophysical Tomography Team in close collaboration with a steering group of industry experts. Professor Jonathan Chambers – Principal Geophysicist and Leader of the BGS Geophysical Tomography Team – introduced the PRIME technology at the event, first providing the context and vision behind its development.
“Many infrastructure assets were constructed a long time ago, to no recognisable engineering standards and often using less than appropriate materials,” explained Jonathan. “These assets, when put under environmental pressures such as excessive rainfall, can become challenging to manage. The concept of remote condition monitoring has been gaining traction, as has the realisation that we can harness technology to give us near real time information on changes in critical structures. In looking for solutions to better manage earthworks assets, PRIME was developed to provide a remote condition monitoring and decision-support system for assessing the internal physical condition of safety critical geotechnical assets, such as embankments, cuttings and dams.”
The PRIME technology is based on non-invasive Electrical Resistivity Tomography (ERT), a geophysical imaging technique that is sensitive to compositional variations in the subsurface as well as changes in groundwater saturation and the presence of contaminants. The benefits of using ERT include the ability to view volumetric information, composition and moisture content within the asset. Combining this state-of-the-art geophysical ground imaging technology with data telemetry and web portal access via ITM’s Calyx™ Online Monitoring Software, forms the PRIME system.
“The overarching vision for the development of PRIME was to make cutting-edge geophysical ground imaging technology relevant, useful and available to the geotechnical community. I’m pleased to say that we have achieved this,” continued Jonathan.
What are the benefits of using PRIME?
After giving a brief introduction to resistivity imaging, Jonathan provided an overview of the benefits of this kind of geophysical imaging, which include:
- Non-invasive – reduces the need for costly or dangerous drilling or excavations
- Provides spatial or volumetric information – which can identify small-scale subsurface processes and can help target further investigations
- Enables early intervention
- Relatively low cost compared to many other approaches
- Rapid – measurements can often be undertaken quickly
Jonathan’s presentation went on to explain the cost and risk benefits of PRIME being used in the management of major assets. An outline of the capabilities of the system was also provided, illustrated with case histories demonstrating its application in real life scenarios, including a landslide site, a stretch of rail cutting, a canal embankment and in the monitoring of leaking underground water pipes.
Applications of PRIME
Designed for targeted deployment to provide long-term monitoring of high risk or critically important structures, or short-term monitoring to determine whether intervention is required, the key applications for PRIME are transportation, water utilities, flood defences, contaminated land, landfill, mining, landslides and agriculture. PRIME is of particular importance at sites where you want to keep boots off the ground, and where access is limited or potentially hazardous.
Following Jonathan’s presentation, Philip Ball – Group Technical Director at SOCOTEC – chaired a panel discussion comprised of industry experts, including: Oliver Pritchard, Consultant Infrastructure Advisory at Arup; Nigel Lee, Principal Geologist at Kier Design Services; Owen Tarrant, Senior Research Specialist, Flood and Erosion Risk Management at Environment Agency and Michael Edwards, Principle Engineer for Network Rail.
Delegates had the opportunity to pose questions, share views on how this technology might benefit their engineering discipline and discuss engineering challenges with the panel. Below you can see a selection of the questions asked, and the resulting answers. More are covered in the WebEx.
“PRIME is now ready for roll-out as a commercial service,” concluded Jonathan. “The BGS is a research organisation and therefore we are not best placed to offer routine commercial monitoring operations, so we are thrilled to be working with ITM Monitoring, who will act as the exclusive delivery agent of PRIME, making this monitoring system available to the industry. The BGS will continue to consult on system design and data interpretation, as well as to develop the PRIME technology further.”
Nick Slater – ITM’s Monitoring Services Director, adds: “We are really pleased to be working with the BGS on the rollout of PRIME. ITM is ideally placed to do this as we’ve been involved in the development of PRIME for several years now, we have expertise in installing and operating geotechnical monitoring systems, and we have Calyx – our web-based portal – which has been interfaced with PRIME to visualise the data generated by the system.”
To speak to a member of the ITM team about the PRIME technology and installation of a system, please contact us on t: +44 (0) 1825 701801 or e: email@example.com.
A sample of the Q&A session:
Is PRIME a remote condition monitoring solution which is used to inform design, gain intelligence about an asset and determine when to intervene, or is it a remote failure detection system where the information is much more binary in terms of whether you react or not?
In this first iteration, PRIME is a remote condition monitoring tool. In future, there will be more opportunity in terms of early warning and failure detection as a greater database of cases is built up and the geophysical information gained allows us to better understand the link between precursor processes to individual failure events.
How quickly can I get the data back from the PRIME instrumentation on-site to our office?
We refer to PRIME information delivery as near-real-time. It can take around an hour for the subsurface scan to be completed. Then you need to allow time to transmit the data back, to process it and to extract the movement information. At present, PRIME does not provide an immediate indication of what is happening on site. This is why we can’t currently rely on PRIME as an immediate failure detection system.
What is the maximum imaging depth of PRIME?
The resistivity technique is entirely scalable. You can deploy it with sensors separated by just a few millimetres looking at very small-scale processes or, it can be deployed with survey lines of a mile in length, with 20 metre separation of sensors. In general, the longer your imaging line or grid, the deeper you can see. The rule of thumb is that imaging depth is approx. 20-25% of line length.
There is a trade-off, however. The system uses a finite number of electrodes, currently the system can address 256. If you spread these sensors out, then you can achieve greater penetration and greater coverage but, as you spread sensors out, the spatial resolution decreases.
Can PRIME be powered by renewables?
The typical installation runs off a fairly small 40w solar panel and for nearly all of the monitoring applications, this is sufficient. Where mains power is available, we will use it, however. Again, there is a trade-off. If we run the system continuously, then the solar panel power set up would not be enough but, for many of the application we are dealing with, one or two scans per day is sufficient and the power set up we have is configured for that.
If you’re deploying this system on a high-risk critical asset, you need to be assured that it’s going to run. Do you have any issues with battery life?
The system is configured to generate regular health logs, informing us on how the system is operating. These health logs are streamed back from the system using the telemetry so we can monitor very carefully how battery levels are being maintained. If we identify any problems we can either modify the monitoring scheme to preserve battery life or we can go out and service the system.
What about theft of the system?
By using a GRP enclosure, our intention was to make the system as inconspicuous as possible, for it to blend into the background. We’ve had a dozen or so installations over the past year and we’ve only had an issue of theft at one of the sites, where the solar panel and the batteries were stolen. Our learning from this was to install the solar panel some distance away from the system enclosure, so that opportunistic thieves don’t necessarily make the link between the solar panel and the enclosure.