关键词: 土, 各向异性, 强度准则, 修正应力法, 被动土压力

Abstract: The modified stress method is adopted in this paper to consider the effect of anisotropy on soil strength. This method introduces the fabric tensor to adjust the relative magnitudes of stress components in different directions, so that anisotropic soil can be equivalent to isotropic soil in the modified stress space. By substituting the modified stress tensor for the ordinary stress tensor, the Mohr-Coulomb strength criterion can be developed to be cross-anisotropic. The form of the criterion remains unchanged, while strength parameters are still constant and independent of the loading direction. This paper compares the relation curves between the internal friction angle and the loading direction according to three different modified stress formulas and analyzes the effect of fabric on the variation of the internal friction angle. Continuous and regular failure envelops are drawn in the deviatoric plane. Meanwhile, triaxial compression and true triaxial test results of different anisotropic geomaterials are predicted. Finally, the cross-anisotropic Mohr-Coulomb criterion is used to calculate the passive earth pressure on the retaining wall in the horizontally sedimentary stratum. The obtained expression is simple and explicit, which verifies the practicability of the modified stress method.

Key words: soils, anisotropy, failure criterion, modified stress method, passive earth pressure