离散元对加固尾砂在干湿循环作用下的细观力学分析

Micromechanical Analysis of Reinforced Tailings by Discrete Element Under Dry Cycle

为探究加固尾砂在干湿循环作用影响下力学性能、力链和尾砂颗粒运动的变化,通过对加固尾砂进行三轴试验和离散元颗粒流(PFC^(2D))模拟试验,分析其力学性能变化趋势,并且探究尾砂颗粒间受力传力和颗粒运动的演变。试验结果表明:加固尾砂峰值应力随着干湿循环次数增加而逐渐递减,但是其峰值应力相较于原状尾砂至少提升2.13倍;在干湿循环作用下,加固尾砂内部力链逐渐加粗,网状粗力链区域增多,且网状粗力链区域发生位置变化;试样破坏碎片数量随循环次数增加而增加,碎片集中区随着循环进行,从试样下部向上部移动;干湿循环造成尾砂颗粒位移情况发生改变,颗粒不同位移区域增加,并在试样上端产生大量不同位移区域,造成试样上端更容易被破坏。

In order to explore the changes of mechanical properties,force chain and particle movement of reinforced tailings under the influence of dry-wet cycle,the triaxial test and particle flow code(PFC^(2D))simulation test of reinforced tailings were carried out to analyze the change trend of mechanical properties,and to explore the evolution of force transmission and particle movement between tailings particles.The test results show that the peak stress of the reinforced tailings gradually decreases with the increase of the number of dry-wet cycles,but its peak stress is at least 2.13 times higher than that of the undisturbed tailings.Under the action of dry-wet cycle,the internal force chain of reinforced tailings gradually becomes thicker,the area of meshed coarse force chain increases,and the position of meshed coarse force chain changes.The number of broken fragments of the sample increases with the increase of the number of cycles,and the fragment concentration area moves from the lower part of the sample to the upper part with the cycle.The dry-wet cycle causes the displacement of the tailings particles to change,and the different displacement regions of the particles increase,and a large number of different displacement regions are generated at the upper end of the sample,which makes the upper end of the sample more easily destroyed.