考虑真实颗粒形状的尾矿动力特性离散元研究

A discrete elemental study of dynamic properties of tailings considering real particle shapes

土体材料由大量单个颗粒组成,颗粒形态对于土体的宏细观力学性质有直接的影响。通过显微观测,考虑颗粒形态效应,对尾矿颗粒进行一系列离散元模拟。通过CT扫描与图像处理技术,研究3组不同围压下真实颗粒试样与圆颗粒试样的液化特征。研究结果表明:尾粉砂颗粒多以粒状和片状形式存在,以边边接触和面面接触为主。离散元试样在液化时会出现“连通带”现象。在不同围压下,圆颗粒试样的动孔压表现为“快—平稳”,动应变发展均呈现“喇叭状”,而真实颗粒试样的动孔压则由低围压时的“快—平稳”变为高围压时的“快—平稳—慢”发展模式,动应变发展则由低围压时的“喇叭状”变为高围压时的“号角状”。2种试样所表现出的孔隙率、配位数与能量发展变化均有所不同。

The soil material consists of numerous individual particles,and the shape of these particles directly impacts the macro-and micro-mechanical properties of the soil.Through microscopic observation and considering particle shape effects,a series of discrete element simulations were conducted on tailings particles.Using CT scanning and image processing techniques,the liquefaction characteristics of real particle samples and circular particle samples under three different confining pressures were studied.The results show that tailing silt particles mainly exist in granular and flaky forms,with edge-edge and face-face contacts predominating.Discrete element samples exhibit a"connective band"phenomenon during liquefaction.Under different confining pressures,the dynamic pore pressure in circular particle samples exhibits a"fast-stable"pattern,and the development of dynamic strain shows a"horn-shaped"pattern.In contrast,the dynamic pore pressure in real particle samples changes from"fast-stable"under low confining pressure to"fast-stable-slow"under high confining pressure,and the development of dynamic strain shifts from a"horn-shaped"pattern under low confining pressure to a"trumpet-shaped"pattern under high confining pressure.Additionally,the changes in porosity,coordination number,and energy development differ between the two types of samples.