GEG were commissioned by CALA Homes to undertake a Phase III Post-demolition intrusive investigation of a 1.2 hectare site in Coventry for the development of 64 No. two and/or three storey residential plots with associated private gardens, access roads and parking.
The post demolition intrusive site investigation comprised the drilling of 7 No. boreholes utilising dynamic sampling techniques to depths ranging from 3.00m to 4.70m bgl of which a total of 2 No. boreholes were installed with standpipes for subsequent gas monitoring; and 11 No. trial pits to a maximum depth of 3.40m bgl. The investigation incorporated chemical sampling/analysis of soils/groundwater and in-situ/ex-situ geotechnical testing.
The GEG Report incorporated human health and groundwater risk assessments and foundation requirements. Due to slightly elevated concentrations of hydrocarbons, GEG recommended a capping layer for sensitive rear/front gardens and landscaped areas. The groundwater risk assessment determined that there was no groundwater risk. GEG considered that the most appropriate and cost effective foundation solution was vibro-stone columns due to the excessive depth of the underlying made ground.
The remedial strategy was approved by the NHBC, Local Authority and Environment Agency.