Shear Behavior and Strain Localization of Kutch Soil

The mechanical behavior of soil mass is governed by its mode of deformation. When homogeneous soil mass is subjected to large deformations, it can create concentrated zones of localized deformations within the soil mass. These non-uniformities can be attributed due to the imposed testing conditions or the imperfections inherited within the soil mass. The initiation and propagation of these localized deformations can strongly impact the mechanical behavior of soil. The non-uniformity due to the testing conditions can be minimized by using lubricated end boundary system. The field conditions can be simulated in a more realistic manner by using lubricated end boundary system as it provides free-free boundary conditions as compared to fixed–fixed boundary conditions in conventional frictional end boundary system. The aim of the current study is to evaluate the shear behavior of silty-sand Kutch soil under lubricated end boundary conditions and correlate the response with strain localization patterns of soil. A series of isotopically consolidated undrained compression (CIUC) tests were performed at varying confining pressures under lubricated end boundary conditions. Digital images of the deforming soil specimen were captured during its shearing stage, and digital image analysis (DIA) was performed to obtain the strain localization patterns of soil specimens at different global axial strain levels at chosen confining pressure. The strain localization analysis exhibited an increased tendency to localized deformations as confining pressure was reduced. The Kutch soil specimens reported the diffused mode of failure for all three confining pressures (100, 200 and 300 kPa).