Rock Mass Rating system
From Wikipedia, the free encyclopedia
 |
This article or section is in need of attention from an expert on the subject. Please help recruit one or improve this article yourself. See the talk page for details. Please consider using {{Expert-subject}} to associate this request with a WikiProject |
The Rock Mass Rating (RMR) system is a geomechanical classification system for rocks, developed by T.Z. Bieniawski between 1972 and 1973.
Contents |
[edit] Definition
The following six parameters are used to classify a rock mass using the RMR system
- Unaxial compressive strength of rock material
- Rock quality designation (RQD)
- Spacing of discontinuities
- Condition of discontinuities
- Groundwater conditions
- Orientation of discontinuities
Each of the six parameters is assigned a value corresponding to the characteristics of the mountain. These values are derived from field surveys. The sum of the six parameters is the "RMR value", which lies between 0 and 100.
[edit] Classification table
Below is the classification table for the RMR system.[1]
| RMR | Rock quality |
|---|---|
| 0 - 20 | Very poor |
| 21 - 40 | Poor |
| 41 - 60 | Fair |
| 61 - 80 | Good |
| 81 - 100 | Very good |
[edit] Applications
Rock Mass Rating has found wide application in various types of engineering projects such as tunnels, slopes, foundations, and mines. It is also adaptable for knowledge-based expert systems.
[edit] Literature
- Bieniawski, Z.T. "Engineering Rock Mass Classifications", John Wiley and Sons, New York, 1989
- — "The Rock Mass Rating (RMR) System (Geomechanics Classification) in Engineering Practices." Rock Classification Systems for Engineering Purposes, 17-34. Philadelphia, Pennsylvania: American Society for Testing and Materials, 1988
