基于系列Drucker-Prager破坏准则评述土坡的稳定性

Comments on slope stability based on a series of Drucker-Prager failure criteria

各种在π平面上等效面积的Drucker-Prager屈服准则,如DP4(Drucker-Prager与Mohr-Coulomb两屈服准则在π平面上的投影面积相等)、DP5(Drucker-Prager与Matsuoka-Nakai两屈服准则在π平面上的投影面积相等)和DP6(Drucker-Prager与Lade-Duncan两屈服准则在π平面上的投影面积相等)等模型都不同程度地模拟了平面应变条件下土体的破坏强度,这就是为什么等效面积的Drucker-Prager屈服准则在二维土坡稳定分析中被推广应用的原因。结合砂土的真三轴强度破坏试验结果,从量化角度论证了DP4模型求出的土坡安全系数可能会保守一些,而DP5和DP6两模型求出的土坡安全系数可能会更真实一些,能更好地发挥材料的承载潜力,因而进一步改善了土坡稳定安全系数的计算精度。

Different equivalent area Drucker-Prager yield criteria onπplane, such as DP4（meaning projection areas of Drucker-Prager and Mohr-Coulomb yield criteria being equal on π plane）, DP5（meaning projection areas of Drucker-Prager and Matsuoka-Nakai yield criteria being equal on π plane） and DP6（meaning projection areas of Drucker-Prager and Lade-Duncan yield criteria being equal on πrplane） yield criteria, can give a approximately estimation for soil failure strength under plane strain condition, this is why these equivalent area Drucker-Prager yield criteria are widely used in two-dimensional slope stability analyses. Combined true triaxial strength failure tests of sand, it is demonstrated from quantitative point that DP4 yield criterion is conservative for safety factor prediction of slope stability; whereas DP5 and DP6 yield criteria, which will exert soil shear strength more effectively under plane strain status, both give a better safety factor predictions for slope stability analyses, thus computation precision of slope safety factor is further improved by using DP5 and DP6 yield criteria in the end.