ABSTRACT
In the early stages of a project, laboratory prepared samples of stabilised soil are tested, in order to assess the stabilising effect, i.e. to what degree the mechanical properties of natural soils are improved by the stabilisation. In order to obtain reliable and reproducible results a suitable and standardised preparation method is essential. Since no satisfactory preparation method existed, it was decided to develop a suitable reference method, to be used within all research projects co-ordinated by The Swedish Deep Stabilization Research Centre. In the new method, the clay and the stabilising agent are mixed in a closed cylinder by a specially designed mixing tool. When mixing is finished, punching of tubes into the stabilised clay forms samples with a suitable shape. Extensive testing of multiple samples shows that the new method makes it possible to determine the undrained shear strength, using unconfined compression tests, within a deviation of ±10% from the average. The deviation using older methods is ±20 to ±30 % from the average. The new method results in samples having about the same undrained shear strength as samples being prepared using the old methods. However, the new method sometimes results in samples with a lower stiffness.
