This paper presents the results of an experimental study of the particle scale mechanisms that underpin creep, on-going deformations under constant external load, in dry non-cemented sand under 1D oedometric compression loading at 2500 kPa. Traditional observations on the boundary of the sample are complemented with simultaneous measurements of the 3D kinematics of both the entire grain assembly and details of grain-scale mechanisms using synchrotron based X-ray tomography at two different spatial resolutions. Both the continuum response and the local grain scale response are captured using two spatial resolutions, i.e. and respectively. The results, for the first time, illustrate that small displacements measured at the boundary can be the result of rather pronounced fracturing at the individual grain scale.
Keywords: Creep; Micro-mechanics; Sand; X-ray tomography.