2026 Geotech Call for Abstracts

Much of the UK’s overhead power lines cross some of the most remote parts of the country. With the push for increased reliance on renewable energy the distribution of electricity from remote on and offshore is as critical as it has ever been. This requires the upgrade and construction of new powerline and underground cale routes. CGL have worked with our clients across Scotland and have provided an innovative monitoring solution. This provides an efficient, accurate and consistent slope stability monitoring across these schemes. The techniques deployed to inform the assessment of geotechnical, slope stability and landslide hazards include derivations of LiDAR data and the use of interferometric synthetic aperture radar (InSAR). The outputs of modelling these elements identifies areas which pose a high risk to infrastructure from slope instability, and informs the requirement for monitoring. To monitor slope movements the use of InSAR has proven itself to be invaluable. The ability to utilise repeat cycles of S- and L-Band InSAR for the assessment of ground movement in remote landscapes with millimetre accuracy further refines initial assessments and can highlight areas where ground conditions pose an ongoing risk to infrastructure. The effects of construction activities and any mitigation measures can be monitored on a site wide scale without the need for costly and installation of equipment. CGL have produced a catalogue of case studies using S- an L-band InSAR data in conjunction with LiDAR modelling to provide contextual remote monitoring of natural slopes and remote infrastructure. The case studies highlighted for presentation include roadway stability and overhead power line route landslide hazard studies.

This presentation will investigate the potential of telemetry data from Continuous Flight Auger (CFA) piling operations to enhance stratigraphic profiling and optimise efficient pile installation. Currently, rig telemetry systems are limited to verifying parameters like pile length and concrete volume. However, torque, penetration rate, and crowd force data can provide valuable insights into subsurface transitions, enabling real-time decision-making during pile installation.

Using machine learning techniques, including supervised and unsupervised learning models, the research analyses extensive telemetry datasets to identify rock levels for end-bearing piles founded in rock. Advanced processing methods, such as the random forest classifier algorithm and K-means clustering, are applied to evaluate the accuracy and reliability of detecting geological layers. Statistical methods are used to provide specific boundary detection between layers. Spatial smoothing is used to detect anomalies that could pose a risk of drilling piles short or excessively long. The findings suggest the practical benefits of telemetry-based stratigraphic profiling for foundation design and construction. Precise identification of rock levels can reduce overly conservative design assumptions, minimising material wastage, machine wear, and project costs. Furthermore, the research underscores the value of collaborative data sharing among contractors to enhance predictive capabilities and achieve broader industry advancements in monitoring while drilling (MWD) applications.

The practical outcome of this research is a system that generates a site-specific model using drilling logs early on a project, whether those are trial bores or a strategic selection of working piles. A simple interface would then confirm the rock level for the operator in situ for each pile position using the trained model, approved by the designers. This work contributes to geotechnical drilling knowledge by demonstrating how telemetry data and machine learning can advance CFA piling practices. It supports ongoing efforts to integrate MWD systems for real-time subsurface characterisation and improved foundation design, allowing more innovative and efficient piling operations.

The A1(M) Leeming to Barton upgrade project in North Yorkshire follows the historic alignment of Dere Street and, at Catterick, passes through a Roman town south of the River Swale. On the North bank a series of Roman earthworks back-filled with archaeological deposits were encountered. These deposits, including pottery, bones, building foundations, and structural earthworks, were deemed of high archaeological value. It was estimated that full excavation would add between six months and two years to the project programme, causing significant delays and cost implications.

Therefore, a strategy for in situ preservation was developed to safeguard the archaeology without compromising construction timelines. A methodology had to be agreed with National Highways and English Heritage to leave these deposits in place whilst protecting them from construction activities.

With no civil engineering precedents for in situ protection of archaeological remains under active construction, a DEFRA and English Heritage-funded agricultural study formed the basis of the approach. This study involved instrumented pseudo-archaeological artefacts, buried and subjected to various farm machinery loads, with resulting stress measurements captured in situ. Back-analysing the study results, the measured profiles could be replicated using classical soil mechanics and linear elastic theory. This permitted the stresses likely to be imposed by construction plant to be assessed using the same methodology.

Additional stress from earthworks was also calculated and added to those from construction plant. Key findings indicate that the stress increases could be kept well below the threshold associated with damage to most fragile archaeological materials. With careful use of a layered approach, protection of the archaeological deposits was achieved. This case study demonstrates that significant archaeological remains can be protected without compromising construction progress. The DEFRA study includes data for all common types of pottery found in the UK, allowing strategies to be developed for future projects.

A changing climate accelerates the deterioration of ageing linear infrastructure, impacting the resilience of our flood defence assets. To address this challenge, we need intelligent monitoring of our ageing assets to understand where and when they might fail, and to intervene earlier to prevent failures. In doing so, we can optimise management and serviceability whilst minimising spend and reducing our impact on the environment and society, resulting in a more sustainable management approach.

Non-intrusive technologies can detect and assess deterioration processes holistically, facilitating data-driven decisions around early-intervention measures. As this case study demonstrates, these early interventions are significantly less expensive and have a lower impact to the environmental and social capital of assets when compared to extensive and intrusive repairs to embankment sections following fully developed piping failures.

AtkinsRéalis, working with the Environment Agency and British Geological Survey, have put this approach into action at Powderham Banks, a 200-year-old flood defence located on the Exe Estuary, Devon. The embankment protects the London to Penzance railway, an RSPB reserve and ~100 residences. In March 2023, a void opened in the crest, accompanied by piping in the landward face, following which the EA tasked AtkinsRéalis with identifying further sections of potential failure. AtkinsRéalis leveraged non-intrusive drone- and geophysics-based techniques to map 'at risk' sections of the embankment, identifying 20 locations that showed evidence of internal deterioration. Within 14 months of the initial survey, 25% of these ‘at risk’ locations failed. A PRIME resistivity monitoring system was subsequently installed at the embankment in late 2024. The near-real-time observations of seepage from the system have facilitated low-impact, low-cost early interventions on the estuary side of the defence, which are significantly cheaper than repairing piping failures to the landward face, thus preserving the social and natural capital of the embankment while lowering maintenance costs and extending asset serviceability.

Constructing the basement for the St John’s Wood Square development offered a unique opportunity to demonstrate the potential for digital and technical innovation through combining advanced 3D finite element modelling with extensive monitoring data. St John’s Wood Square occupies 2.2ha on the former St John’s Wood Barracks site in London, delivering a luxurious residential scheme comprising apartments and townhouses over one of the largest basements in the UK (130mx160m, single to triple storey). The development is adjacent to highly sensitive assets, including Transport for London St John’s Wood Station structures and tunnels, water and gas buried services, high value residential properties directly bordering the site and the 200-year-old Grade 2 listed Riding School barracks building.

Robert Bird Group (RBG) developed a viable construction proposal to enable the 156,000m3 excavation to proceed within the stringent movement requirements imposed by third parties. Understanding the complexity of the project, RBG introduced a back-analysis and observational method approach to effectively manage the geotechnical risks related to the basement excavation. RBG undertook advanced 3D finite element modelling of the entire substructure and superstructure construction sequence to accurately confirm predicted movements and impact on the existing sensitive assets at each critical phase throughout construction. Leveraging the comprehensive suite of monitoring data, a purpose-built tool (GeoMotion) was created by RBG as a smart digital innovation to streamline extraction, processing and visualisation of data.

The combination of advanced numerical modelling and monitoring back-analysis and observational method, using a data-driven approach beyond industry practice, unlocked the construction of this large basement without adversely impacting the existing sensitive structures. This offered significant value engineering and risk management for the project, providing a better control of the site activities whilst safeguarding the integrity of the third-party assets, demonstrating a significant advancement in the industry standard approach.