加载条件和粒径对颗粒材料黏结–滑移特征影响的研究

Influence of Loading Conditions and Particle Size on Stick-Slip Characteristics of Granular Materials

将自然断层中常见的黏结–滑移现象和颗粒材料特性相结合,采用玻璃珠颗粒材料开展室内直剪试验和离散元数值分析,通过改变法向应力、剪切速率以及颗粒粒径,探究了加载条件和粒径大小对颗粒材料黏结–滑移特征的影响。模型试验和数值模拟结果表明:玻璃珠颗粒在受剪状态下发生周期性黏结–滑移,摩擦愈合和黏结–滑移周期是表征颗粒黏结–滑移特性的关键参数;摩擦愈合随剪切速率的增大而减小,随颗粒粒径的增大而增大,而法向应力对摩擦愈合影响较小;黏结–滑移周期和摩擦愈合表现出正相关,黏结–滑移周期随剪切速率增大而明显减小;颗粒间的摩擦咬合作用是影响黏结–滑移行为的重要因素。

Combining the common bonding slip phenomena in natural faults with the characteristics of granular materials,indoor direct shear tests and discrete element numerical analysis using glass bead particles were conducted.By changing the normal stress,shear rate,and particle size,the influence of loading conditions and particle size on the stick-slip characteristics of granular materials were investigated.Model experiments and numerical simulations indicate that glass bead particles exhibit periodic stick-slip under shear conditions,and the frictional healing and stick-slip period are key parameters characterizing the stick-slip characteristics of particles.The frictional healing decreases with increasing shear rate and increases with increasing particle diameter,while the normal stress has a smaller impact on the frictional healing.Stick-slip period and frictional healing show a positive correlation,with the stickslip period significantly decreasing with increasing shear rate.The frictional interlocking between particles is an important factor influencing stick-slip behavior.