屈服准则对土质边坡稳定安全度计算的影响分析

Influence of Yield Criterion on Calculating Safety Degree of Soil Slope

分析了在应用有限元强度折减法计算土质边坡稳定安全度时,屈服准则对计算结果的影响。Mo-hr-Coulomb准则和Drucker-Prager准则是岩土工程中较常用的屈服准则,计算结果表明Mohr-Cou-lomb准则得出的安全度偏小,Drucker-Prager准则与参数α和k的选取直接相关,其中用Mohr-Cou-lomb内接圆及等面积圆得出的安全度比较合理;统一强度理论可以考虑岩土材料的中间主应力效应及拉压差效应,在边坡稳定分析中可以发挥材料的承载潜力。

In computing safety degree of the soil slope stability by nonlinear FEM strength reduction method, the influence of yield criterion on the calculation results is analyzed. Mohr - Coulomb and Drucker - Prager criteria are commonly used in civil engineering. Calculation results show that the safety degree using Mohr - Coulomb criterion is smaller, which is related to the parameters such as α and k when using Drucker - Prager criterion. The safety degree is more reasonable when a and k is computed by the circle connecting inner vertexes of Mohr - Coulomb circle and by the circle whose area is equal to the area of Mohr - Coulomb circle. At the same time, the unified strength theory is used for slope stability analysis because it can reflect the effects of the middle F,rimary stress and the difference between pulling strength and pressing strength. Results show that unified strength theory is useful for slope stability analysis and it can make the material strength being utilized fully.