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.