横观各向同性土强度与破坏准则的研究

建立横观各向同性土的破坏准则必须考虑其应力水平和材料横观各向同性的综合影响。本文通过分析横观各向同性土的试验规律，基于横观各向同性土的强度随SMP面（空间滑动面）和沉积面的夹角减小而变小这一假设，建立横观各向同性土的峰值强度表达式。提出了一个关于横观各向同性土的峰值强度和应力张量函数的各向异性变换应力张量。在各向异性变换应力空间，横观各向同性土体被认为是各向同性材料。将变换应力与SMP准则结合，建立了横观各向同性土的三维破坏准则。分别采用具有横观各向同性的 Santa Monica 海滩砂土和 San Francisco 海湾黏土真三轴试验数据验证了该破坏准则的合理性。预测结果与试验结果的对比表明，本文提出的横观各向同性破坏准则能够合理的描述横观各向同性对土体强度特性的影响。

Study on strength and failure criterion of cross-anisotropic soil

The combined effects of stress level and material cross-anisotropy should be considered when constructing failure criterion for cross-anisotropic soils. Test results for cross-anisotropic soils were deeply analyzed. Based on the hypothesis that the smaller the angle between the SMP (spatially mobilized plane) and the depositional plane is, the lower the strength is, the function of cross-anisotropic peak strength is proposed for cross-anisotropic soils. A transformed stress tensor is proposed as function of cross-anisotropic peak strength and stress tensor. In the transformed stress space, cross-anisotropic soils can be assumed as isotropic material. A three-dimensional cross-anisotropic failure criterion was proposed by combining the transformed stress tensor with the isotropic SMP failure criterion. The criterion is validated through comparisons with experimental data of cross-anisotropic Santa Monica Bench sand and San Francisco Bay Mud. The comparisons have demonstrated that the proposed cross-anisotropic failure criterion can describe the effect of cross-anisotropy on soil strength reasonably well.