One of the two independent key parameters of the Hoek–Brown failure criterion, m_i, is calculated using 3-axial test data consisting of at least five major and minor principal stresses and the regression method. In the absence of 3-axial test data, the guideline chart, which provides m_i values, is commonly used in practice. However, m_i values calculated from regression analyses have a much greater spread than that proposed in the Guideline. Therefore, simplified models, based on some strength properties, have been proposed to calculate m_i values. But some of these prediction models were based on a few types of rock and limited data. In this study, an alternative method for predicting m_i using internal friction angle (ϕ), which is determined from classical 3-axial test, is proposed. First a brief description of the proposed method was given and a summary on the existing methods for predicting m_i was discussed with their limitations, and the data selection criteria used by the authors were also described. In order to assess the prediction performance of the proposed method, a database, consisting of 125 data sets and representing a total of 26 different rock types, was compiled from a well-known dataset and published sources. Results of the comparisons between the proposed method and some of the current prediction methods mainly suggested that the proposed method yields the best m_i predictions. It is also noted that for sedimentary rocks, the ranges of m_i estimated from this method were closer to those proposed in the Guideline chart.

Hoek-Brown 失效准则的两个独立关键参数之一m _i使用由至少五个主要和次要主应力组成的 3 轴测试数据和回归方法计算。在没有 3 轴测试数据的情况下，提供m _i值的指南图在实践中通常使用。然而，从回归分析中计算出的m _i值的分布比指南中提出的要大得多。因此，已经提出了基于一些强度特性的简化模型来计算m _i价值观。但其中一些预测模型是基于少数几种岩石和有限的数据。在这项研究中，提出了一种使用内部摩擦角 ( φ ) 预测m _i的替代方法，该方法由经典的 3 轴测试确定。首先对所提出的方法进行了简要描述，并对现有的预测m _{i的方法进行了总结。}讨论了它们的局限性，还描述了作者使用的数据选择标准。为了评估所提出方法的预测性能，一个由 125 个数据集组成并代表总共 26 种不同岩石类型的数据库是从一个著名的数据集和已发布的来源编译而来的。所提出的方法与一些当前预测方法之间的比较结果主要表明，所提出的方法产生了最好的m _i个预测。还需要注意的是，对于沉积岩，用这种方法估计的m _i范围更接近于指南图表中提出的范围。