高应力状态粗粒土颗粒会发生颗粒破碎现象,颗粒粒径分布发生变化,大大增加了颗粒的压缩性。本文通过对生石膏、钙质砂两种均匀级配砂进行高应力下的一维压缩试验,探究初始粒径及材料性质对于试样屈服应力及压缩系数的影响。采用PFC-3D对粗粒土颗粒一维压缩过程中的颗粒破碎现象进行三维模拟,不仅实现了颗粒破碎可视化,还探究了初始粒径、粒间摩擦系数、破碎情况以及破碎准则对压缩特性的影响。结果表明:随着初始粒径的增大,屈服应力随之减小,而压缩系数随之增大;材料性质及破碎准则均可对压缩特性产生不同程度的影响,粒间摩擦系数及破碎情况则基本无影响;试验和模拟过程中,颗粒粒径均由最初的均匀分布向着分形分布发展,PFC-3D可以较好地对颗粒破碎现象进行模拟。
When coarse soil particles are under high stress, particle breakage will occur, particle size distribution will change, and finally the compressibility of particles will become larger. In this paper, through one-dimensional compression tests of gypsum and calcareous sand under high stress, the effects of initial particle size and material properties on the yield stress and compression coefficient of samples are explored. The phenomenon of particle breakage during one-dimensional compression of coarse soil particles can be simulated by discrete element software. This paper uses PFC-3D to simulate the process in three dimensions, which not only realizes the visualization of particle breakage, but also explores the influence of initial particle size, friction coefficient between particles, breakage and breakage criteria on the compression characteristics. The test and simulation results show that the yield stress decreases and the compression coefficient increases with the increase of the initial particle size; Both material properties and crushing criteria have different effects on the compression characteristics, while the friction coefficient between particles and crushing conditions have little effect. In the process of experiment and simulation, the particle size changes from the initial uniform distribution to the fractal distribution. PFC-3D can well simulate the particle breakage phenomenon.
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