Please use this identifier to cite or link to this item:
|Scopus||Web of Science®||Altmetric|
|Title:||Pre-peak and post-peak rock strain characteristics during uniaxial compression by 3D digital image correlation|
|Citation:||Rock Mechanics and Rock Engineering, 2016; 49(7):2541-2554|
|H. Munoz, A. Taheri, E. K. Chanda|
|Abstract:||A non-contact optical method for strain measurement applying three-dimensional digital image correlation (3D DIC) in uniaxial compression is presented. A series of monotonic uniaxial compression tests under quasi-static loading conditions on Hawkesbury sandstone specimens were conducted. A prescribed constant lateral-strain rate to control the applied axial load in a closed-loop system allowed capturing the complete stress–strain behaviour of the rock, i.e. the pre-peak and post-peak stress–strain regimes. 3D DIC uses two digital cameras to acquire images of the undeformed and deformed shape of an object to perform image analysis and provides deformation and motion measurements. Observations showed that 3D DIC provides strains free from bedding error in contrast to strains from LVDT. Erroneous measurements due to the compliance of the compressive machine are also eliminated. Furthermore, by 3D DIC technique relatively large strains developed in the post-peak regime, in particular within localised zones, difficult to capture by bonded strain gauges, can be measured in a straight forward manner. Field of strains and eventual strain localisation in the rock surface were analysed by 3D DIC method, coupled with the respective stress levels in the rock. Field strain development in the rock samples, both in axial and shear strain domains suggested that strain localisation takes place progressively and develops at a lower rate in pre-peak regime. It is accelerated, otherwise, in post-peak regime associated with the increasing rate of strength degradation. The results show that a major failure plane, due to strain localisation, becomes noticeable only long after the peak stress took place. In addition, post-peak stress–strain behaviour was observed to be either in a form of localised strain in a shearing zone or inelastic unloading outside of the shearing zone.|
|Keywords:||Uniaxial compression test; Post-peak behaviour; Strain localisation; Digital image correlation|
|Description:||First online: 07 March 2016|
|Rights:||© Springer-Verlag Wien 2016|
|Appears in Collections:||Civil and Environmental Engineering publications|
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.