The development of 118 housing plots was proposed within the Fox Valley area of Stocksbridge, South Yorkshire. The area was a disused former steelworks site with deep deposits of granular made ground. The development was selected for housing due to the regeneration of the town centre and surrounding road networks.
The development required 5 visits to the site.
Granular made ground deposits consisting typically of a loose to very dense black ashy sand were present across the whole of the site to depths up to 9.5m. The made ground was underlain by firm / stiff clays on to sandstone. Areas of the site contained shallow made ground deposits over sandstone rock where the valley sides were present.
A Vibro Stone Column solution was proposed along with pre-augering to achieve a consistent bearing capacity of the soils beneath the foundations. A semi-raft foundation design was adopted in the deep made ground soils whilst a traditional ground beam foundation was adopted in the shallow made ground soils.
Due to the presence of deep fills, a stringent testing regime was adopted including 37no. plate load tests and 34no. dummy foundation tests to validate the success of the treatment.