Mohr-Coulomb Shear Strength Criterium
For the M-C criterium of shear strength, the analysis method of slope stability differs for:
- drained conditions: for the slope stability calculations to determine equilibrium conditions on the slip surface (circular, polygonal), the effective stress is considered according to the equation N*tgφef + cef*l.
- undrained conditions: in the case of the total stress, the calculation of passive forces on the slip surface (circular, polygonal) uses the equation cu*l.
For effective stress, the basic parameters such as the angle of internal friction and cohesion are inputted. The particular values are obtained from a geotechnical survey or from laboratory experiments. If this data is not available, it is possible to exploit the built-in database of soils, which contains values of selected characteristics of soils. The characteristics of rocks are not listed in the built-in database, these parameters must be defined manually. Approximate parameters of rocks are presented in the theoretical part of the Help herein.
In some countries, it is customary to specify both shear strength parameters φu, cu for the total stress. In this case, it is necessary to specify the task as an effective stress using parameters φef, cef in the "Slope Stability" program.