The Behavior of Expansive Particle Packing – DEM Simulation Using PFC3D Code

Abstract

Ground upheaving occurs in expansive soils as a result of the absorption of water molecules onto the clay surface. The refractory materials deposited underground can also expand via the hydration process transforming from magnesium oxide to magnesium hydroxide. In this study, the behavior of expansive particle packing is investigated using Discrete Element Model (DEM) simulation. During simulation, the volume of the individual particle expands 2.5 times the initial volume. A couple of expansive particle fractions were considered ranging from 0.2 to 0.8. During the simulation, a constant vertical confining stress is applied and only vertical displacement is allowed. During expansion, the horizontal stress and vertical expansion is monitored as well as porosity. The results show that the earth pressure coefficient starts increasing from k = 0.5 initially, and finally reaches to k = 1.5 for the expansive particle fraction = 0.2 or k = 2.0 for the expansive particle fraction larger than 0.4. The porosity of the particle packing decreases during expansion. The particle packing under higher confining stress showed lower porosity.