Simulation of Sand Column Failure with Actual Particle Size

砂柱の崩壊は，砂粒子が大きく移動することで，砂柱が大変形する，最も基本的な砂の破壊現象の一つである．本研究では，砂柱の崩壊現象を実験・観察し，砂粒子の動きを一粒毎に計算できるDEM（Discrete Element Method）（1, 2） を用いてこの現象を数値的に解析した．実験では，粒径が約1 mm のガラスビーズを実験材料とし，PIV（Particle Image Velocimetry）（3） 解析によって砂柱が崩壊するときの変位及び変形速度を得た．数値解析においては，粒子サイズを実験と合わせてパラメトリックスタディを行い，実験における砂柱崩壊の再現を試みた．その結果，砂柱崩壊現象のシミュレーションには，減衰係数が重要な役割を果たすことが明らかとなった． There is one crucial parameter that governs the simulation of sand column failure. Our goal was to identify the parameters for applicability of DEM (Discrete Element Method) to simulate the failure of sand columns, one of the most fundamental phenomena underlying sand failure. In this study, we conducted an experiment on the failure of sand columns. We chose glass beads that have a grain diameter of approximately 1 mm as the material for the experiment. We employed PIV (Particle Image Velocimetry) analysis to obtain the profile of displacement and the speed of transformation during the failure process. We have simulated the sand column failure process using DEM and tried to reproduce the deformation that we observed in our experiment. We made the particle size in our analysis the same as that in the experiment, and conducted a parametric study that involved changing parameters, such as the friction angle between particles, the damping coefficient, and rolling friction. Our results indicate that the damping coefficient plays a significant role in simulations of sand column failure