The 1.5 hectare site was previously occupied by railway sidings and was redeveloped with the construction of eight student accommodation blocks each between six and eight storeys. The buildings were to be constructed using piled foundation but due to the risk of vibration during piling works, Cognition was asked to consider alternative options to piled foundations. Cognition carried out trials to demonstrate that ground stabilisation would provide geotechnically suitable subgrade material on which to construct conventional raft foundations.
Cognition was contracted by Longcross Construction to undertake soil stabilisation works at the Castle Mill site in Oxford. Cement stabilisation was carried out to 3.5m below ground level extending 1m below the water table. This approach eliminated the risk of vibration and improved the natural ground to allow for raft foundations. The key elements of the works included;
Cognition completed the soil stabilisation works and delivered an alternative approach to piling work which eliminated the risk of vibration, allowing all work to be completed safely. Student accommodation buildings were constructed successfully without complex alternative foundations.