利用室内动三轴试验对云南粉土进行动力特性研究，分析饱和粉土达到应变破坏时，最大往返剪切作用面上初始剪应力比与往返剪应力比的关系，提出相应的破坏应力条件模型.结果表明：破坏应力条件模型为二次抛物线，能充分拟合初始剪应力比与往返剪应力比的关系，回归效果高度显著；对于应变标准，破坏应变取为2.5%时，粉土初始剪应力比临界值约为0.24；破坏应变取为5.0%时，初始剪应力比临界值约为0.26~0.27.这些结果将为斜坡之下饱和粉土单元破坏应力状态的分析提供一些试验参考.%Based on dynamic triaxial tests in the laboratory,the dynamic characteristic of Yunnan silt was studied. The relationship between the initial shear stress ratio and cyclic shear stress ratio on the maximum cyclic shear surface was analyzed by using the strain failure criterion,and the failure stress condition model was proposed. The results indicate the failure stress condition of Yunnan silt can be represented by a quadratic parabola ,which can well fit the relationship between initial shear stress ratio and cyclic shear stress ratio ,and the regression effect is highly significant. The critical value of initial shear stress ratio of silt was about 0.24 when the failure strain was 2.5%,and it was about 0.26-0.27 when the failure strain was 5.0%. The results can provide some references for failure stress analysis of saturated slit element on slope.
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