基于非线性破坏准则的岩体剪切强度参数确定方法

Determination of the Shear Strength Parameters of Rock Mass Based on Nonlinear Failure Criterion

剪切强度预测是岩体稳定性分析的重要内容,为了采用Hoek-Brown非线性准则描述岩体的剪切强度参数,利用理论推导和数值拟合的方法,探讨了Hoek-Brown参数到Mohr-Coulomb参数的转换过程,并分析了非线性准则中各个参数对于剪切强度参数的影响。结果表明,通过大量数据拟合回归的方法可确定剪切强度参数与Hoek-Brown准则参数之间的关系;随着地质强度指标GSI的增大,岩体的剪切强度参数c和准均不断增大,黏结力较内摩擦角对于岩体地质强度指标的变化更为敏感;二者随mi的变化幅度均不大,GSI对于岩体强度的影响大于mi。

The prediction of the shear strength is an important part in the analysis for rock mass stability. The shear strength parameters of the rock mass are described by the Hock-Brown nonlinear failure criterion in this paper. And a transformation procedure from the Hoek-Brown parameters to the Mohr-Coulomb parameters is proposed. In the transformation procedure, the theoretical analysis and data fitting method are used. The influences of each parameter in the nonlinear failure criterion on the shear strength parameters are analyzed. It is shown that the relationship between the shear strength parameters and Hoek-Brown criterion parameters can be determined by fitting a large amount of data. With the increase of geological strength index GSI, the shear strength parameters c and 6 increase gradually. The effect of cohesion on the rock geological strength index is more sensitive to the friction angle. But their variations with the mi are not that large, which indicates that the GSI has a larger effect on the rock strength than on mi. The results can give some guidance for the real practice.