A hazard assessment (considering a number of geological, geomorphological and hydrogeological factors) indicated a potential risk from solution features within the underlying chalk bedrock. Foundation design recommendations were provided to mitigate risks from chalk solution, along with advice on the siting of soakaways so as to minimise the possibilities of initiating/re-activating chalk solution.
A new care home development was proposed on a greenfield site in an area prone to chalk dissolution. The site was underlain by Terrace Gravels over the Upper Chalk. ESP undertook an initial hazard assessment to evaluate the potential for solution features. This was followed by a geophysical survey to identify anomalous ground, which could represent potential solution features.
- Desk study review.
- Subsidence Hazard Rating for Natural Cavities – Chalk bedrock.
- Trial pitting and shallow boreholes.
- Gas monitoring.
- Geophysical surveying.
- Recommendations for foundation and soakaway design to mitigate risks from chalk solution.