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黄土节理的抗剪强度及变形规律对工程稳定性有重要影响,但目前对此的研究尚不充分.为此本次研究首先采集了黄土天然垂直节理土样,然后采用室内大型直剪试验方法,研究了黄土天然节理的剪切强度及变形性质,最后与小型直剪试验结果进行对比,得到了尺寸效应对黄土节理剪切强度的影响规律.结果发现,大型直剪试验得到黄土节理剪切峰值内摩擦角为47.37°,小型直剪试验值为35.17°;黄土节理直剪试验存在尺寸效应,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;法向应力较小时,初始剪切刚度较大,应力-应变曲线存在峰值;法向应力较大时,初始剪切刚度较小,应力-应变曲线无峰值,剪切强度随应变增大而增大,最终趋于稳定.
The shear strength and deformation law of loess joints have an important influence on the stability of the project, but the research on them is not yet sufficient.Therefore, this study first collected natural vertical loess joints, and then adopted the large-scale indoor direct shear test method , The shear strength and deformation properties of natural joints of loess were studied and compared with the results of the small direct shear tests.The influence of size effect on the shear strength of the loess joints was obtained.The results show that the large- The peak internal friction angle is 47.37 °, and the small direct shear test value is 35.17 °. The size effect of the loess joint in the direct shear test exists. The sample size mainly affects the contribution of the relief surface roughness to the shear strength. The larger the shear strength The larger the normal stress is, the larger the initial shear stiffness is and the bigger the stress-strain curve is. When the normal stress is larger, the initial shear stiffness is smaller and the stress-strain curve has no peak. The shear strength changes with strain Increase and increase eventually stabilize.