黄土节理的剪切强度特性对于含节理黄土工程的稳定性有重要影响,为此在大量野外调研的基础上,采集典型黄土节理土样,首先对不同节理表面形态进行分类以制备试样,然后采用室内直剪试验研究了含水量对黄土节理剪切强度参数的影响规律,并与室内大型直剪试验对比,研究尺寸效应对剪切强度的影响,最后依据试验结果研究了节理剪切应力-位移规律.研究表明:黄土节理的抗剪强度关系符合摩尔-库伦准则,且黏聚力可忽略不计;随含水量的增加,黄土节理峰值内摩擦角最初的变化幅度较小,当大于某个含水量值时,峰值内摩擦角减小幅度变大,其变化规律可用指数形式进行描述;试样尺寸主要影响节理面起伏度对剪切强度的贡献,尺寸越大,其剪切强度也越大;其剪切应力-位移曲线属非线性屈服剪切型曲线,并构建了本构模型,对初始剪切刚度研究发现其随含水量增加减小,随正应力增加呈线性增加.%The shear strength characteristics of loess joints significantly affect the stability of project with joint loess.Based on a large number of field investigations,the suitable sites are selected to collect the loess vertical joints.The first is to classify different joint surface morphologies for sample preparation.Then,laboratory direct shear test is used to study the influence of water on loess joint shear strength parameters,and comparing with lab large-scale direct shear test to study the influence of the size effect on the shear strength.Finally,according to the results,the law of joint shear stress and displacement is studied.The results show that the loess joint shear stress-shear displacement relationship curve belongs to nonlinear yield shear type curve;loess joint shear strength is corresponded with Mohr Coulomb criterion,and cohesion is so small that almost negligible;as the water content increases,loess joint peak friction angle initial tends to a lesser extent,when more than a moisture content value,the peak friction angle is reduced significantly.The loess joint strength with the variation of the amount of water available index form are described;the sample size mainly affects the joint surface's contribution to the shear strength,and the greater the size is,the greater shear strength is;the yield shear stress and displacement curve is nonlinear shear curve,and the constitutive model is built to study the initial shear stiffness.The results show that the initial shear stiffness decreases with the increase of water content,and increases linearly with the increase of normal stress.
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