The site is located within Frys Hill Park, on the outskirts of Oxford. At present it is a public amenity park, comprised of grassland, playing fields, a children’s play area and a skate park. The northern boundary is formed by the “Northfield Brook”. The park is fully open to the public and so the surface expression of a subsidence feature required immediate attention in order to determine if a risk was posed to the general public and wider park.
We commenced with obtaining detailed historical and geotechnical records for the location, which indicated that in the location of the feature the Northfield Brook has been re-routed to the north, having previously flowed through the study site.
Geological and historical information indicated that the north part of the study area was likely underlain by a cover of Made Ground, resulting from historical filling with arisings from an adjacent sewage works. Available information indicated that the Made Ground was underlain by Alluvial Deposits and Sandstone bedrock.
A detailed site walkover was undertaken and identified the feature. Extending the walkover across the wider park site identified other areas of potential settlement/subsidence such as raised or previously reinstated manhole covers. Evidence of the anticipated Made Ground at the surface was visible during the walkover.
We provided the Client and design team with a thorough phase 1 desk study, providing an assessment of a number of potential causes, and explanation of how each may have led to the surface expression of the feature. As part of this project we implemented a detailed review of available historical and geological information, then expanded our understanding through a comprehensive site walkover and visual assessment. Our findings and conclusions have allowed the Client to consider their likely next steps on how to further assess the feature and any others that may, over time, become apparent.
We have extensive experience in assessing features such as this and routinely implement studies of this nature where geotechnical hazards, such as subsidence, settlement, Limestone solution or Mining Hazards (see our coal mining risk assessment services) lead to surface expression features which may pose a risk people and property.
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Get in touch with our team via our email, enquiries@earthsciencepartnership.com or phone number, 02920 813385 and we’ll be very happy to help with and discuss any geotechnical engineering project requirements you may have.
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