Abstract
Systems and methods are described for monitoring temporal and spatial moisture content changes in clay embankments using electrical resistivity tomography (ERT) imaging. The methodology is based upon development of a robust relationship between fill resistivity and moisture content and its use in the transformation of resistivity image differences in terms of relative moisture content changes. Moisture level and moisture content movement applications are exemplified using two case histories from the UK. The first is the BIONICS embankment, near Newcastle (NE England), which was constructed in 2005 using varying degrees of compaction of a medium plasticity sandy, silty clay derived from the Durham Till. The second is a Victorian embankment south of Nottingham (Central England), constructed in 1897 using end tipping of Late Triassic siltstone and mudstone taken from local cuttings. Climate change forecasts for the UK suggest that transportation earthworks will be subjected to more sustained, higher temperatures and increased intensity of rainfall. Within the context of preventative geotechnical asset maintenance, ERT imaging can provide a monitoring framework to manage moisture movement and identify failure trigger conditions within embankments, thus supporting on demand inspection scheduling and low cost early interventions.
Highlights
Engineered slopes, embankments, canals, earth dams, sea walls and flood defences are increasingly susceptible to catastrophic failure due to changes in global climatic conditions and land use
These case histories demonstrate that the construction method, deterioration history and distribution of composite materials within the embankment control engineering performance, especially, the spatial and temporal variation of groundwater and its influence upon key geotechnical properties controlling strength and stability
BIONICS, a modern clay embankment that was built up in layers, which are clearly recognised within the resistivity images
Summary
Engineered slopes, embankments, canals, earth dams, sea walls and flood defences are increasingly susceptible to catastrophic failure due to changes in global climatic conditions and land use. We provide two case histories: firstly, from the BIONICS research embankment, Nafferton Farm, Northumberland, UK [14,21] constructed using varying amounts of compaction in 2005 from sandy, silty clay derived from partially sorted Durham Till; which includes identification of individual lifts from 2D resistivity sections across the embankment transect; and secondly, from an embankment along the former Great Central Railway near East Leake, Nottingham, UK [2,17,19] constructed via end-tipping of materials derived from the East Leake Tunnel cutting to the south; which includes identification of fill regime changes in a 2D resistivity section along the axis of the embankment, dynamic, seasonal wetting and drying fronts moving through a 2D transect of the embankment and a demonstration of the potential application of 3D volumetric images of moisture movement and geotechnical property visualisation for planning maintenance These case histories provide the context for a broad discussion relating to the foundation for new risk-based asset management practices incorporating automated, electrical imaging technologies into early intervention decision processes, such as proactive drainage planning
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
