Slope equivalent mohr-coulomb strength parameters for rock masses satisfying the hoek-brown criterion

The upper bound theorem of limit analysis is employed to calculate the equivalent MC cohesion coefficient and friction angle to meet the demands of software written in terms of the Mohr-Coulomb (MC) failure criterion when the rock mass failure follows the modified HB failure criterion for slopes in limit state. A MC failure criterion, which is tangent to the actual modified HB failure criterion, is used to calculate the rate of external work and internal energy dissipation. The equivalent MC friction angle is obtained when the objective function is minimized. The equivalent MC friction angles and cohesion depend not only on the nonlinear HB failure criterion but also on the rock slope angles.