This report presents and discusses the results of a series of laboratory Californian Bearing Ratio (CBR) tests and in situ Dynamic Cone Penetration (DCP) tests undertaken on seven materials. The materials ranged from a manufactured 'tree soil' of sand and peat, to crushed granite aggregates that met the requirements for a Type 1 sub-base and a 6F1 capping. The effect that the dry density of the materials had on the results of such tests was also investigated. It was found that reasonably robust correlations could be established between the results of CBR and DCP tests, and also between the results of these tests and the dry density of the materials. Such correlations enable the results of DCP tests to be used to estimate the in situ CBR or dry density of the materials. This work has been undertaken as part of a research contract between Transport for London (Street Management) and a research team consisting of Richards, Moorehead & Laing Ltd, TRL Limited and the Tree Advice Trust.

Want to know more about this project?