E-Thesis 411 views 164 downloads
Geophysical Characterisation and Monitoring of Earth Embankment Dams / RICHARD COTTRELL
Swansea University Author: RICHARD COTTRELL
Abstract
Geophysics has become fundamental in characterising earth embankment dams and identifying preferential seepage pathways, problem areas, and structural defects. The issue of non-uniqueness is profound in the interpretation of geophysical data, with features often attributed to multiple potential sour...
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Swansea, Wales, UK
2023
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MSc by Research |
| Supervisor: | Kulessa, B. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa63575 |
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| Abstract: |
Geophysics has become fundamental in characterising earth embankment dams and identifying preferential seepage pathways, problem areas, and structural defects. The issue of non-uniqueness is profound in the interpretation of geophysical data, with features often attributed to multiple potential sources. This project tackles this issue by applying a multidisciplinary approach comprising traditional techniques to a study site in South Wales. These techniques comprised ground conductivity, magnetometry, and Electrical Resistivity Tomography (ERT). The computation of normalised chargeability data from an Induced Polarisation (IP) survey, normally used for mineral exploration, was applied to delineate between clay and moisture rich areas. This eliminated the issue of non-uniqueness between these two subsurface conditions. The application of these techniques led to successful characterisation of the embankment in terms of its engineered and natural components and identified a potential seepage pathway attributed to surface waters.The Self-Potential (SP) method was evolved into a monitoring solution, building on the research and development of TerraDat Ltd’s SPiVolt system. A methodology was developed to efficiently fabricate and install an SP monitoring network. SP monitoring confirmed the presence of the preferential seepage pathway hypothesised through the characterisation survey and identified a second pathway through the dam’s core.Dŵr Cymru Welsh Water have since used the results of this project to design a targeted grouting campaign and install surface drainage at the site. Comprehensive understanding of the material composition and temporal variations of subsurface conditions is considered essential for ensuring dam and reservoir owners achieve their aims of climate resilience and asset protection. The geophysical characterisation and monitoring methodology presented in this thesis provides an effective low-cost solution that can be applied to multiple scenarios such as landslide investigations, coal tip stability assessments and other hydrogeological problems. |
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| Keywords: |
Geophysics, Monitoring, Dams and Reservoirs |
| College: |
Faculty of Science and Engineering |
| Funders: |
KESS 2 East |