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http://dx.doi.org/10.7474/TUS.2019.29.3.172

Analytical Formula for the Equivalent Mohr-Coulomb Strength Parameters Best-fitting the Generalized Hoek-Brown Criterion in an Arbitrary Range of Minor Principal Stress  

Lee, Youn-Kyou (Department of Coastal Construction Engineering, Kunsan National University)
Publication Information
Tunnel and Underground Space / v.29, no.3, 2019 , pp. 172-183 More about this Journal
Abstract
The generalized Hoek-Brown (GHB) failure criterion developed by Hoek et al. (2002) is a nonlinear function which defines a stress condition at failure of rock mass. The relevant strength parameter values are systematically determined using the GSI value. Since GSI index is a value quantifying the condition of in-situ rock mass, the GHB criterion is a practical failure condition which can take into the consideration of in-situ rock mass quality. Considering that most rock mechanics engineers are familiar with the linear Mohr-Coulomb criterion and that many rock engineering softwares incorporate Mohr-Coulomb criterion, the equations for the equivalent friction angle and cohesion were also proposed along with the release of the GHB criterion. The proposed equations, however, fix the lower limit of the minor principal stress range, where the linear best-fitting is performed, with the tensile strength of the rock mass. Therefore, if the tensile stress is not expected in the domain of analysis, the calculated equivalent friction angle and cohesion based on the equations in Hoek et al. (2002) could be less accurate. In order to overcome this disadvantage of the existing equations for equivalent friction angle and cohesion, this study proposes the analytical formula which can calculate optimal equivalent friction angle and cohesion in any minor principal stress interval, and verified the accuracy of the derived formula.
Keywords
Generalized Hoek-Brown failure criterion; Friction angle; Cohesion; Linear best-fitting; Orthogonal projection;
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Times Cited By KSCI : 1  (Citation Analysis)
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