Improvement of fine-grained and cohesive soils by vibro replacement stone columns
We have seen from the description of the development of the deep vibratory processes that vibro stone columns extend the limits of application of these ground improvement methods from predominantly noncohesive into fine-grained cohesive soils. With regard to the grain size distribution of the soils to be improved, vibro replacement stone columns are used when conditions prevail as represented by areas outside of zone B in Figure 3.13. In the following, it will be shown that the load-carrying capability of soils so improved depends primarily from the interaction of the stone columns with the surrounding soil. The columns are supported by the soil which they replace and which requires therefore a certain minimum strength.