准静态侵入颗粒介质的底边界效应仿真分析

Based on the spherical discrete element method, this paper studies the bottom boundary effect of granular media, simulates the quasi-static intrusion of rigid body cylinders into particle media with limited thickness to the bottom boundary, and explores the relationship bet-ween the resistance of intruder and the depth of intrusion. The results show that the resistance-depth curve of the cylindrical quasistatic intrusion particle layer to the bottom of the pool has a linear hydrostatic pressure in the front section and an exponential growth form in the back section near the bottom boundary. However, there are fluctuations in resistance within a few particle sizes from the bottom, and the wavelength is approximately the same length as the particle diameter. Furthermore, the particles in the inverted conical curing zone connected to the cylindrical bottom have dynamic renewal. The curing zone collapses when the intrusion is close to the bottom boundary, where the local particle blocking determines the resistance growth trend. Additionally, the particle force chain below the bottom of the cylinder is transformed into a "bottom-bottom" force chain between the bottom of the cylinder and the bottom of the particle pool when it approaches the bottom boundary. The decrease in the average number of particles after the force chain is squeezed explains the volatility of the resistance oscillation.