Strength and stiffness of laboratory-mixed specimens of stabilised Norwegian clays

In situ ground improvement by deep mixing the soil with stabilising agents or binders as lime, cement, cement kiln dust or a combination of these is the most common method applied in the Nordic countries. In Norway, soil stabilisation with deep mixing has been applied to soft-to-medium stiff clays with sensitivity ranging from about 5 to over 100. This paper presents a large database of laboratory results from laboratory-stabilised Norwegian clays. For example the data show that shear strength of the stabilised clays decreases when the water-to-binder ratio (i.e. total clay water-to-binder content ratio) increases, and that the stiffness development is mainly controlled by time. Some observations from more advanced laboratory testing on samples taken from stabilised columns in the field highlight the anisotropic behaviour of the stabilised clays and the increase in strength with in situ stresses. The data presented can be used as a guide on the selection of binder mixes for specific project applications and it should always be supplemented by testing on site-specific laboratory-mixed specimens.