基于广义Hoek-Brown准则的边坡稳定性强度折减法数值分析

Hoek-Brown屈服准则作为估计完整岩石或节理岩体剪切强度的半经验准则,已成为岩体强度预测及计算领域应用最广泛的准则之一,并在边坡极限平衡法计算中得到了广泛应用,但很少应用于数值模拟计算领域。本文结合工程实例,以广义Hoek-Brown屈服准则建立数值计算模型,并基于强度折减方法计算边坡安全系数,经与等效Mohr-Coulomb屈服准则数值模拟及极限平衡计算对比,得出基于Hoek-Brown屈服准则的模拟计算结果与其它方法一致并且正确的结论。并认为不同屈服准则条件下的边坡潜在滑移面位置及变形特点存在差异,原因在于不同的屈服准则采用了不同的流动法则。与Mohr-Coulomb屈服准则相比,Hoek-Brown屈服准则采用基于应力水平的塑性流动法则更加体现了节理岩体的变形和破坏特点,可有效反映岩体的非线性破坏特征,更加接近工程实际,适于节理岩体的强度计算及稳定性分析。

Numerical simulation analysis on strength reduction for slope of jointed rock masses based on gereralized Hoek-Brown failure criterion

As a semi-empirical rule for estimating shear strength of integral rock or joint rock masses, the Hock-Brown failure criterion has been one of the most useful criteria in forecast and calculation of rock masses strength. Moreover, it has widely applied in calculation of slope limit equilibrium, but rarely used in numerical simulation calculation. Numerical simulation model was established based on the gereralized Hock-Brown failure criterion, and the factor of safety slope was calculated based on the strength reduction method. Compared with the numerical simulation of equivalent Mohr-Coulomb failure criterion and the calculation of the limit equilibrium, it was concluded that the calculated results based on Hock-Brown failure criterion were similar to those calculated by other methods and because of different flow rules were used in different failure criteria, the position of the sliding surface and the deformation characteristics had some difference under different failure criteria. Compared with the Mohr-Coulomb failure criterion, gereralized Hock-Brown failure criterion could more properly exhibit the deformation and failure characteristics of jointed rock masses as it used plastic flow rule based on stress level. Hock-Brown failure criteria could effectively reflect the nonlinear failure characteristics of rock masses, and it made the calculated results closer to practical situation.