基于加州承载比试验的隧道弃渣颗粒接触力场形状影响因素分析

Analysis of Influence Factors on the Shape of Contact Force Field of Tunnel Slag Particles Based on California Bearing Ratio Test

对级配碎石而言,不同的颗粒表面性质会影响颗粒接触力场形状、大小及梯度,进而改变试样所受约束力。分析加州承载比(California bearing ratio,CBR)试验过程中试样侧板及底板的受力演变,探究试样颗粒细观参数对试样颗粒接触力场及试样约束力的影响。通过对比不同刚度比、摩擦系数与黏结强度(设定其比值为1下)对试样接触力场形状的影响。结果表明:以刚度比值6为界,随法向刚度的增大,颗粒接触力场长细比先增加后减小;随摩擦系数或黏结强度增大,接触力场长细比相应减小。考虑颗粒相对运动中黏结强度比中法向及切向参数作用不同,以黏结强度比4为界,随法向黏结强度增大,其接触力场长细比先增加后减小;随切向黏结强度增大,所得接触力场长细比变化趋势则为先减小后增加。研究成果可为研究隧道弃渣制成的级配碎石颗粒细观参数与其接触力场形状间关联性提供一定参考。

Different particle surface properties will affect the shape,size and gradient of particle contact force field,and then change the binding force on the sample,for graded crushed stone.The stress evolution of sample side plate and bottom plate during California bearing ratio(CBR)test was analyzed,and the influence of sample particle micro-parameters on sample particle contact force field and sample binding force was explored.By comparing the influence of different stiffness ratio,friction coefficient and bonding strength(set the ratio as 1)on the shape of the contact force field of the sample.The results show that the slenderness ratio of the particle contact force field increases first and then decreases with the increase of the normal stiffness,taking the stiffness ratio of 6 as the boundary.The slenderness ratio of contact force field decreases with the increase of friction coefficient or bond strength.The normal and tangential parameters in the bond strength ratio in the relative motion of particles have different effects.Taking the bond strength ratio 4 as the boundary,the slenderness ratio of the contact force field increases first and then decreases with the increase of the normal bond strength.And with the increase of tangential bond strength,the slenderness ratio of the contact force field decreases first and then increases.The research results can provide some reference for the study of the correlation between the micro-parameters of graded crushed stone particles made from tunnel waste slag and the shape of its contact force field.