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对边坡岩体软弱夹层进行现场剪切试验,根据试验结果对软弱夹层的剪切变形本构关系进行了分析。常用的剪切变形本构模型有双曲线模型和指数模型,但试验结果表明,这两种模型计算得到的一定剪切变形下的剪应力比实际结果偏小。通过对两种模型的研究发现,由双曲线模型和指数模型得到的剪切刚度Ks分别为剪应力的2次和1次函数,且均为剪应力的一元函数,不能准确地反映软弱夹层的剪切变形本构关系。在此分析基础上,建立了剪切刚度-剪应力的幂函数模型,幂函数模型的精确性在于刚度指数n值的确定,n值可根据试验结果采用回归分析法获得。根据试验结果建立了不同法向应力下的软弱夹层剪切变形的幂函数模型。计算结果表明,幂函数模型与实际情况更为接近,表明用幂函数模型描述软弱夹层的剪切应力-位移关系是合理的。
The field shear test is carried out on the soft interlayer of the slope rock mass, and the shear deformation constitutive relation of the soft interlayer is analyzed according to the test results. Commonly used shear deformation constitutive model hyperbola model and exponential model, but the experimental results show that the shear stress calculated by the two models under a certain shear deformation is smaller than the actual results. Through the study of the two models, it is found that the shear stiffness Ks obtained from the hyperbolic model and the exponential model are the second and the first order of shear stress, and they are all the univariate functions of shear stress, which can not accurately reflect the Shear deformation constitutive relationship Based on this analysis, the power function model of shear stiffness-shear stress is established. The accuracy of the power function model lies in the determination of the stiffness index n. The value of n can be obtained by regression analysis according to the test results. According to the experimental results, the power function model of the shear deformation of soft interlayer under different normal stresses is established. The calculation results show that the power function model is closer to the actual one, which shows that it is reasonable to describe the shear stress-displacement relationship of the weak interlayer by power function model.