Characterisation of the Halden silt

NGI recently established a research site on a natural silt deposit to accommodate some of the challenges related to intermediate soils. This study briefly summarises the geological history and the preliminary geotechnical characteristics of the Halden silt deposit. The stratigraphy at the site consists of four main units. Two structureless silt units sit between a 4.5 m thick layer of sand and a 6 m thick deposit of clay. Soil behaviour type charts classify the silt deposit as transitional soils/silts to low Ir clays. Classification tests indicate that these soils are low plasticity silts with very similar mineralogical content. The results presented will form a useful reference to engineers working on similar intermediate soils worldwide.