Thesis
Utilizing microseismic monitoring in the investigation of brownfield sites
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17311
- Person Identifier (Local)
- 201992924
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Technical difficulties in the redevelopment of brownfield sites stem mainly from the uncertainties in the shallow subsurface. Often the use of the site has not been adequately documented. Unmapped buried infrastructure, e.g. concrete or steel tanks, can pose delays to site remediation works and incur significant, unexpected costs. Traditionally, in assessing brownfield sites for redevelopment, intrusive investigations are carried out. Such investigations are expensive and can only provide information at discrete locations. Non-intrusive methods, including electrical resistivity/conductivity and ground penetrating radar (GRP), have also been applied to brownfield sites. Their ability in detecting pollution e.g. buried canisters, is often restricted due to unfavourable on-site conditions (clay soils or concrete surface layers). Seismic could overcome such challenges but their application for the shallow subsurface suffers from time consuming surveys, poor signal to noise ratios and high computational and expert elicitation requirements for processing and interpretation of the acquired data which is done later in the office. These are prohibiting factors, often to the expense of the site investigation efforts. This thesis explores this research and technology gap by proposing a different methodology approach for identifying the presence of buried objects of dimensions down to 1 m x 1m x1m and at depths between 1 and 3 m. The workflow is based on active microseismic recordings and the principle of seismic wave reflection but the analysis and interpretation are different to traditional seismic reflection surveys. Using numerical simulations in FLAC3D, this study investigated the changes in surface seismic wave amplitude and frequency over distance from the active source, as the seismic wave interacts with a heterogeneous subsurface and how these changes can be used to map what lies beneath. The numerical simulation results revealed higher wave amplitudes at monitoring stations positioned above or approximately 2 to 4m in lateral distance from the buried objects. Spectral analysis highlighted concentrated seismic energy at these locations and this was quantified by calculating the area under the Power Spectral Density (PSD) curve. The area above and around the buried object exhibited consistently the maximum seismic energy while the actual value of this concentrated energy differed based on the material of the object, which for this research was either (a) concrete, (b) steel or (c) PVC. Results were validated through available historical field data and a field experiment specifically designed and executed to verify the numerical simulations at a chosen site with made soil. The results in this thesis show that the workflow is simpler, easy to implement, computationally faster and considerably cheaper than existing geophysical methods for site investigation. The workflow in this thesis was carried out manually but it can be easily automated and can be used for real-time preliminary site investigation of brownfield sites to identify areas that require a more comprehensive assessment, ensuring effective environmental and industrial site management.
- Advisor / supervisor
- Pytharouli, Stella
- Parastatidis, Emmanouil
- Douglas, John
- Resource Type
- DOI
- Funder
Relations
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PDF of thesis T17311 | 2025-06-03 | Public | Download |
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File | 2025-05-06 | Private |