Model : Q-SYSTEM

The Q-value may be used for classification of the rock mass around an underground opening, as well as for field mapping. This means that the Q-value may be influenced by the blasting on the underground opening. The Q-value in an undisturbed rock mass may be different. The Q-system is a classification system for rock masses with respect to stability of underground openings. Based on estimation of six rock mass parameters, a Q-value for a rock mass can be calculated. This value gives a description of the rock mass quality. The different Q-values are related to different types of permanent support by means of a schematic support chart. This means that by calculating the Q-value it is possible to find the type and quantity of support that has been applied previously in rock masses of the similar qualities. The Q-system can therefore be used as a guideline in rock support design decisions and for documentation of rock mass qualityThe Q-system is developed for use in underground openings. However, the system can also be used for field mapping, core logging and investigations in a borehole, but it is important to have in mind that in such cases some of the parameters may be difficult to estimate. The Q-values from field mapping and boreholes will therefore often be more uncertain than those mapped in an underground opening, and should be handled with some care.
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