A large-strain radial consolidation model incorporating soil destructuration and isotache concept

Abstract

Prefabricated vertical drains (PVDs) are widely applied for soft soil improvement to accelerate the consolidation process. The soil destructuration caused by mandrel-driven PVD installation, the varying strain-rates with time and the occurrence of large-strains in soft soils are commonly encountered, however, there is currently a lack of analytical model that can capture the combined effects of these issues. This study thus presents a semi-analytical solution for large-strain radial consolidation model that incorporates the effects of destructuration and strain-rate based on the isotache concept. The proposed method is compared with previous radial consolidation models through an appropriate case study (i.e., Ballina Bypass trial embankment), where the destructuration and isotache parameters could be determined experimentally. The results show that the current method adopting the isotache concept can predict the consolidation behaviour with improved accuracy, especially in large-strain situations where soil destructuration has been ignored. Furthermore, a parametric study is carried out using the proposed model, which helps clarify when the effects of large strain and varying strain-rate must be considered in practical designs.