基于H-B准则的各向异性边坡岩体强度参数修正研究

CORRECTION OF STRENGTH PARAMETERS FOR ANISOTROPIC SLOPE ROCK MASS BASED ON H-B PRINCIPLES

在岩质边坡的稳定性计算分析中,各向异性岩体抗剪强度参数的合理取值直接决定了分析成果的可靠性。为充分考虑岩体各向异性对边坡工程的影响,本文基于H-B强度准则,利用边坡岩体质量分类体系CSMR替代RMR,对参数mb、s进行修正,并由此进一步计算得到各向异性边坡岩体的等效M-C强度参数。通过工程实例,计算比较了金沙江某水电站导流洞出口边坡在相同基岩条件、不同开挖设计方案下强度参数修正前后的边坡稳定安全系数。研究结果表明,岩体各向异性对边坡稳定性影响较大,未考虑岩体各向异性的岩体参数用于边坡稳定性计算时不能准确反映边坡的实际稳定性状态;而经过各向异性修正后,导流洞出口边坡两种设计方案下的整体稳定安全系数计算结果分别为1.11和1.70,与工程地质定性、半定量评价结果基本相符。通过本文提出的方法对边坡各向异性岩体参数进行修正,并在此基础上对边坡整体稳定性进行计算分析是可行的。

The calculation result of stability of anisotropic rock slope is directly dependent on the value of shear strength parameters of the rock mass.In order to take the influence of rock anisotropy on slope stability into account,we use CSMR instead of RMR in the H-B strength criterion,and modify the parameters m b and s.Then,the equivalent M-C strength parameters of anisotropic rock mass can be obtained.They are combined with the calculation of the slope engineering at the exit of the diversion tunnel of a hydropower station in Jinsha River.The safety factors of the slope stability before and after the correction of the strength parameters under the same bedrock conditions and different excavation design schemes are calculated and compared.The results indicate that the stability of the slope is greatly affected by the anisotropy of rock mass.Without considering the anisotropy of rock mass,the stability of slope cannot be accurately reflected in the calculation result of slope stability.After anisotropy correction,the calculation results of slope safety factors of the two design schemes are 1.11 and 1.70 respectively,which are basically consistent with the qualitative and semi-quantitative evaluation.In summary,the method for correcting the parameters of anisotropic rock mass of slope is feasible.