Study on particle loss-induced deformation of gap-graded soils: role of particle stress

Deformation induced by finer particle loss is an important phenomenon during suffusion of gap-graded soils. This study focuses on the role of particle stress played in the particle loss-induced volumetric deformation. Discrete element simulations are performed to generate loss of finer particles with prescribed stress contribution, i.e. the contribution of particle stress to the macroscopic stress. Variations of volumetric strain, epsilon v, with the stress contribution, C sigma e, of eroded finer particles present two distinct patterns, that is, transition pattern, i.e. epsilon v has extremely small values at relatively small C sigma e and increases rapidly as C sigma e exceeds the transition point near C sigma e = 0.01%, and constant pattern, i.e. epsilon v reaches a rather large value at extremely small C sigma e and varies little with the increment of C sigma e. A transformation from constant to transition pattern is observed for the epsilon v-C sigma e curves with the increment of the coordination number, Zstrong, of the load-carrying skeleton. The threshold of Zstrong for the transformation is around 3.71 for a relatively small eroded fraction (<= 10%), while it is 3.96-4.09 for a relatively large eroded fraction (>= 30%), in which the eroded fraction is the volume percentage of the eroded finer particles within the finer fraction.