冻结速率对Q2黄土性状影响的试验研究

 对不同含水量洛川Q2黄土开展不同冻结速率条件下土样结构细观分析及室内直剪试验。结果表明：(1) 含水量较低时，随着冻结速率的提高，土样低密度区统计频率有所增加，中密度区统计频率几乎无变化，高密度区统计频率稍有减小，冻结速率对土样各密度区影响不大；黄土样含水量较高时，冻结速率对低密度区影响较大，对高密度区影响较小，含水量越大，这种影响也越大。(2) 冻结速率较慢时，水分冻胀作用对黄土的性状影响不明显。当冻结速率较快时，黄土体内的水分来不及迁移到冻结锋面就冻结，在黄土体内冻胀；当冻结冰的体积大于其在黄土体内的自由膨胀空间体积时，黄土体体积稍有增加，黄土密度和黏聚力减小；含水量越大，体积增加越大，土体密度及黏聚力减小程度也越大。冻胀力使得黄土内大孔隙所占的比例有所下降，土颗粒间的接触点增多，从而使得土体内摩擦角增大。冻结速率越快，含水量越大，土体内摩擦角的增加量也越大。

TEST STUDY OF EFFECT OF FREEZING SPEED ON BEHAVIOR OF Q2 LOESS

Microscopic analysis of soil mesostructure and direct shear test for Q2 loess with different water contents under different freezing speeds are conducted.The results show as follows:(1) When the water content of loess sample is low,with the increase of freezing speed,the statistical frequency of low-density area increase a little,while the statistical frequency of middle-density area scarcely changes and that of high-density area decreases a little.So the freezing speed has little effect on each density are...