Listening to Infrastructure

Infrastructure is vital for society - for economic growth and quality of life. Existing infrastructure is rapidly deteriorating, the rate of which will accelerate with increasing pressures from climate change and population growth, and the condition of the large majority of assets is unknown. Stewardship of infrastructure to ensure it continuously performs its function will be a colossal challenge for asset owners and operators. The performance of new infrastructure assets must be monitored throughout their life-cycle because they are being designed and constructed to withstand largely unknown future conditions. The UK must be better prepared to face these grand challenges by exploiting technology to increase understanding of asset deterioration and improve decision making and asset management.

This research is central to EPSRC's priority area of Engineering for Sustainability and Resilience. The goal is to transform geotechnical asset management by developing new, low-cost, autonomous sensing technologies for condition appraisal and real-time communication of deterioration. This new approach will sense Acoustic Emission (AE) generated by geotechnical assets. AE is generated in soil bodies and soil-structure systems (SB&SSS) by deformation, and has been proven to propagate many tens - even hundreds - of metres along structural elements. This presents an exciting opportunity that has never been exploited before: to develop autonomous sensing systems that can be distributed across structural elements (e.g. buried pipes, pile foundations, retaining walls, tunnel linings, rail track) to listen to AE - analogous to a stethoscope being used to listen to a patient's heartbeat - and provide information on the health of infrastructure in real-time. The idea to use AE sensing to monitor geotechnical assets in this way is novel - it is expected to lead to a disruptive advance in monitoring capability and revolutionise infrastructure stewardship.

AE has the potential to increase our understanding of how assets are deteriorating, which could lead to improved design approaches, and to extract more information about asset condition than existing techniques: not only deformation behaviour, but also, for example, changes in stress states, transitions from pre- to post-peak shear strength, and using correlation techniques it will be possible to locate the source of AE to target maintenance and remediation activities. AE sensing will also provide real-time warnings which will enable safety-critical decisions to be made to reduce damages and lives lost as a result of geotechnical asset failures.

The number of asset monitoring locations required per unit length to achieve sufficient spatial resolution will be less than other monitoring techniques, and significantly lower cost. Piezoelectric transducers, which sense the AE, are now being developed at costs as low as a few tens of pence per sensor - this recent technological advance makes this research timely. AE sensors could be installed during construction to monitor condition throughout the life-cycle of new-build assets (e.g. HS2), and retrofitted to existing, ageing assets.

This will be the most fundamental and ambitious investigation into the understanding of AE generated by SB&SSS yet attempted. The findings will mark a major leap forward in scientific understanding and our ability to exploit AE in novel asset health monitoring systems. The fellowship aims to develop robust diagnostic frameworks and analytics to interpret AE generated by geotechnical assets. This will be achieved using a powerful set of complementary element and large-scale experiments. The outcomes will be demonstrated to end-users and plans will be developed with collaborators for: full-scale field testing with in-service assets to demonstrate performance and benefits in intended applications and environments; and implementation in commercial products that could have significant societal and economic impact.

The outcomes of this research have the potential for impact with exceptional reach and significance world-wide. This work will develop new and improved infrastructure health monitoring capability, which will benefit communities exposed to risks posed by geotechnical assets, in addition to the organisations that design, construct and own/operate geotechnical infrastructure.

The potential significant economic and societal impacts of Dr Smith's research are through commercialisation and global deployment (Technology Readiness Level 9) in the medium to long term (expected to be 10-15 years). This will transform geotechnical asset management through enabling targeted and timely intervention, and real-time warnings of limit states (serviceability and ultimate) which will protect people and infrastructure.

The fellowship impact plan has been formulated to engage end-users, develop plans for exploitation and to inspire, inform and educate general public groups.

Fellowship impact activities will include:
- The fellowship will have an industry advisory panel comprising an asset owner (Severn Trent Water), contractor (Costain) and consultant (CH2M). These end-users have been involved in developing this proposal and confirmed their plans for co-creation and engagement with the research from conception through to commercialisation; this will ensure the research and development is informed by user needs and expectations. Regular meetings will be held with these end-users, which will facilitate two-way knowledge exchange. The advisors will share industry challenges and expertise to inform both the research work packages and the impact activities, and Dr Smith will share the research progress. Two workshops will be held to bring together the advisory panel with other practitioners, in addition to technology providers (e.g. electronics engineers and computer scientists), to engage a range of end-users in the research.
- Applications will be developed for further funding with partners and collaborators to support full-scale field testing with in-service geotechnical assets to demonstrate the performance and benefits of the research in its intended applications and environments. This will progress the research through TRLs and build evidence to support commercialisation. It is envisaged that commercialisation will be through licensing to a technology provider(s) that offers products to appropriate end-users.
- A high profile end of project dissemination event will be held at, e.g., One Great George Street in London (ICE headquarters) to draw a large audience. This will be an opportunity to engage a range of end-users, share the research outcomes (e.g. demonstration of the prototype analytics), steer the future direction of the research and plan exploitation.
- To further engage end-users Dr Smith will: participate in industry-led events such as Ground Engineering conferences (e.g. Instrumentation and Monitoring) and the British Geotechnical Association's annual conference; and publish articles in trade outlets such as Ground Engineering and New Civil Engineer magazines.
- Short, high-profile news stories will be coordinated with Loughborough University's press office and project partners to disseminate key achievements, events, papers and outcomes. This could lead to radio, TV, news and web coverage for the research.
- A dedicated fellowship website will be developed to report research progress, in addition to a social media presence (e.g. @Alister_Smith10). These outlets will be used to disseminate to academia, industry and the wider public.
- Exhibition materials including a video and interactive physical model will be developed to facilitate engagement with practitioners at industry events and general public groups at outreach events.
- Dr Smith will become a STEM ambassador to engage with and inspire young people to pursue a STEM career.