Abstract
The numerical challenges that arise in modelling shear bands in soft sensitive (SS) clays have not yet been fully resolved. Convincing and well-accepted solutions have yet to be found. This paper presents some novel information related to the shear band phenomenon in SS clays. In this study, the hypothesis is that the generation and dissipation of excess pore pressure from shear bands could regularise the strain softening and result in a mesh independent shear band thickness. The generation and dissipation of excess pressure is modelled by a coupled consolidation process. The simulation aims at modelling two counteracting mechanisms in the SS clay. First, the shear band narrows because of strain softening. Second, the internal pore water pressure drainage reduces the rate of strain softening. This counteracting mechanism provides an inherent regularisation technique for SS clays. This study presents some numerical results involving these two counteracting mechanisms. This study also shows that an inherent internal parameter applicable for SS clays can be defined by the ratio between soil permeability and the applied strain rate. In the case of SS clays, the range of this parameter varies from 0 to 0.0002 mm.
Acknowledgements
This study was carried out by the author as part of his doctoral study. The author would like to acknowledge the valuable guidance of Professor Steinar Nordal (Geotechnical Division, the Norwegian University of Science and Technology (NTNU)), Dr. Hans Petter Jostad (Norwegian Geotechnical Institute, Norway), Dr. Geir Svanø (SINTEF, Norway) and Dr. Lars Andresen (Norwegian Geotechnical Institute, Norway). The International Centre for Geohazards, (ICG) and NTNU are acknowledged for providing financial support for this study.