不同应力路径下土体的变形特性与破坏特性

在固结不排水加荷与卸荷两种情况下，基于土体常规的三轴压缩试验结果和真三轴平面应变试验结果，指出不同的应力路径下土体具有不同的变形特性和破坏特性，并且这些特性差异的根本原因在于不同的应力路径，有着其球应力p和广义剪应力q与球应力p的比值q/p的不同变化趋势。最后，依据Matsuoka-Nakai破坏准则和其相应的转化型式，进一步探讨了其破坏参数k2值的确定方法。试验检测的结果表明，Matsuoka-Nakai破坏准则能给出土体较为准确的破坏强度预测结果。

Deformation and failure characteristics of soil mass under different stress paths

For soil samples of same soil mass,based on traditional consolidation undrainage triaxial compression tests and true triaxial undrainage plane strain tests under loading and unloading conditions,it is pointed out that soil sample possesses different deformation characteristics and failure characteristics when soil sample is imposed on different stress paths;and these different characteristics are reflected by different changing tendency of average principal stress and ratio q/p of soil sample.At last,according to Matsuoka-Nakai failure criterion and its corresponding new transferred expressing formula,its strength failure parameter k2 value is optimized;and test results show that the Matsuoka-Nakai failure criterion can give a reliable strength failure prediction for soil mass.