Characterization of Smear Zone Caused by Mandrel Action

In this study the smear zone due to vertical drain installation is studied using a large, in-situ sample to capture the realistic characteristics of the smear zone in relation to the in-situ soil structure. The smear zone extent for Bulli clay (New South Wales, Australia) is quantified on the basis of normalised permeability and the reduction in the water content prior to consolidation. The permeability and compressibility of the soil are used to determine the extent to which the soil surrounding the PVD had become disturbed. In laboratory testing, the soil consolidation behaviour due to a prefabricated vertical drain (PVD) is studied using a large scale consolidometer apparatus.