The application called RMR calc returns the Rock Mass Rating (RMR) value and its classification based on Bieniawski (1993).
A full Version with email function and InSitu Elastic modulus of deformation Em [GPa] (Young's Modulus) is available here
This system of rock mass classification is widely used in geomechanics and rock mechanics and allows to relate quality ratings to geomechanical parameters of the rock mass in excavations foundations and tunnel support.
To classify a rock mass using the RMR system the following six parameters are used
1. Uniaxial compressive strength of rock material.
2. Rock Quality Designation (RQD).
3. Spacing of discontinuities.
4. Condition of discontinuities.
5. Groundwater conditions.
6. Orientation of discontinuities.
The parameters are inserted in an easy and intuitve way by using slide bars.
These ratings are added to give a value of RMR between 0 and 100.
Geotechnical engineers working with tunnels slopes in rock and foundations will obtain a coarse indication about Friction Angle and Cohesion of the Rock Mass.