Where the load of the structure proposed, or the quality of the underlying ground dictates, foundations may need to be supported on piles or geotechnically-improved ground (as opposed to traditional concrete filled strip or pad foundations). Government driven policy in the construction industry over the last few decades, has been towards the redevelopment of previous used "brownfield" land. Where this land is contaminated in some way a foundation risk assessment (or piling and penetrating ground improvement risk assessment) maybe required by either the Environment Agency or Local Authority regulators (as part of a planning permission) to ensure there is no risk of mobilising contamination that had previously been "locked-in" by the site's geological make up.
Here at Geo-Integrity we have undertaken many piling risk assessments across Oxfordshire, The Cotswolds, The West Midlands and East Anglia. We have to assess the proposed piling or ground improvement methodology in conjunction with the site geology and the type of contamination encountered. There are then six basic scenarios (as seen below) that need to be considered for the specific site and its conditions. These include the risk of driving contaminated land downwards into an aquifer; or opening up a pathway for ground gas to enter the proposed structure; for example. Once these scenarios have been assess, the most appropriate piling or ground improvement technique can be employed, along with appropriate mitigating factors and QA/QC measures, to ensure that both geotechnical and environmental objectives are met, and that the structure can be completed successfully.
If you have been asked to provide a Piling Risk Assessment for a planning condition and would like some free advice, please contact us on this email or phone on 01280 816409