Estimation of the equivalent Mohr–Coulomb parameters using the Hoek–Brown criterion and its application in slope analysis

Abstract

The linearisation of the Hoek–Brown failure criterion is a commonly encountered problem in rock mechanics. The fact that the minor principal stress used for estimating the equivalent Mohr–Coulomb parameters is the stress at failure cannot be ignored. This article proposes a method for estimating the most likely position of any arbitrary stress point that corresponds to the minimum shear strength on the Hoek–Brown curve. The interval of the minor principal stress at failure, which is employed in the existing equivalent estimation methods, is determined from the actual stress level of the rock mass. The Hoek–Brown failure envelope is divided into several zones, which enables its actual stress gradient variation to better match its curvature. The proposed method is applied to analysis of a slope example. The results show that, as the actual Hoek–Brown strength curve of each material is more finely divided, both the safety factor of the slope and the location of the slip surface based on the equivalent Mohr–Coulomb model agree more closely with those obtained from the Hoek–Brown model.

Keywords:

• Best fitting
• cohesive strength
• friction angle
• Hoek–Brown criterion
• safety factor

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the National Key R&D Program of China (Grant No. 2017YFC1501000), the National Nature Science Foundation of China (Grant No. 41772321), the Science and International Cooperation Project of Sichuan Province (Grant No. 2018HH0082), the Scientific Research Fund of Sichuan Provincial Education Department (Grant No. 18ZA0045) and the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project (Grant No. SKLGP2016Z016).