中文摘要：

对强度理论进行了深入的论述，剖析了莫尔-库仑剪切屈服准则，依据此准则，在主应力空间（三轴仪平面）、偏平面和大小主应力子午面上直观地描绘了在普通三轴仪上进行各种三轴压缩、三轴伸长试验的应力路径和平面应力条件下的应力路径，考虑土体为不抗拉或弱抗拉材料，建议采用张拉-莫尔-库仑剪切复合屈服准则和张拉-剪切-体积复合屈服准则来分析土体的屈服和破坏行为，并结合张拉-莫尔-库仑剪切复合屈服准则对现行有限元数值计算方法中按载荷步进行加、卸载分析时的应力路径进行了探讨。

英文摘要：

Discussions on strength theories were made deeply. The Mohr-Coulomb＇s shear yield criterion was anatomized. Based on the criterion, the stress paths of tri-axial compression and tension tests with ordinary tri-axial instruments were depicted intuitively in the 3D principal stress space （plane of tri-axial instrument） and in the deviatoric plane and the meridional plane of the maximum and minimum principal stresses. The stress paths under the condition of plane stresses were also depicted. Considering soils as a material with weak or no tensive strength, the composite yield criterion of tension and Mohr-Coulomb＇s shear and the composite yield criterion of tension, shear and volume were proposed to analyze the yield or failure behaviors of soils. The stress paths of loading and unloading in existing finite element methods were also discussed by using the composite yield criterion of tension and Mohr-Cloulomb＇s shear.