# title
Soil improvement with vibrated stone columns - Influence of pressure level and relative density on friction angle

# abstract
The application of gravel for improvement of soft soils with pile-like vibrated stone columns has attracted a considerable attention during the last decade. For the design of such a soil improvement, friction angle of the fill material depends markedly on pressure level and relative density. Additionally, size, distribution and shape of grains, together with their mineralogical composition also influence the mechanical behaviour of the soil skeleton in the stone columns. A review of own and published experimental data on gravel and rockfill materials shows that densely prepared specimens yield in most cases very high friction angles lying above 50 at common normal stresses. Thus, conventional design values of 40 are usually too conservative. Furthermore, it is reported on direct and indirect measurements of density inside stone columns installed in situ and on small-scale model tests of stone columns in the laboratory. By exposing vibrated stone columns produced by the Keller method it could be shown that their in situ void ratio corresponds to the maximum density represented by eminaccording to DIN 18126.  2009 Taylor & Francis Group.

# publicationOutlet
Geotechnics of Soft Soils - Focus on Ground Improvement - Proceedings of the 2nd International Workshop on Geotechnics of Soft Soils

# authors[].organizations[].label
College of Agriculture and Life Sciences