Rock mass rating

The RMR value or RMR index ( rock mass rating ) is a classification system for rock. It was 1972/1973 developed by ZT Bieniawski. The system is used in geotechnical engineering for tunnels, caverns, mines, slopes, foundations, etc.. However, the RMR value can not answer all the questions; he is only an estimation and approximation.

Definition

The following six parameters are required to classify a rock according to the RMR method:

Each of the six parameter is assigned a value corresponding to the mountain properties. The rock mass properties are evaluated with field measurements, using forms. The six parameters are then summed to form a sum; the sum of the RMR value which is between 0 and 100.

Classification table

The mountain goodness is classified according to the RMR value into one of five levels ( very good to very bad).

The RMR value always applies to a mountainous area with more or less uniform properties. Therefore, the mountain must be divided into such areas. The boundaries of such areas may, for example, Be interference.

Application

The RMR value you can specify, for example, the necessary dimensions, construction methods or Auffahrmethoden of tunnels. Also as an input to expert systems, it is suitable, or in the application of fuzzy logic techniques.

Other classification systems in addition to the RMR value are: