Abstract #29m <f_n
The rock mass quality Q-value was originally developed to assist in the empirical design of tunnel and cavern reinforcement and Y_'3pX,
support, but it has been used for several other tasks in rock engineering in recent years. This paper explores the application of Q and %P@V7n
its six component parameters, for prediction, correlation and extrapolation of site investigation data, and for obtaining first oM ey^]!
estimates of some input data for both jointed distinct element and continuum-approximation modelling. Parameters explored here ~U"puEftbs
include P-wave velocity, static modulus of deformation, support pressure, tunnel deformation, Lugeon-value, and the possible S<fSoU+RJ
cohesive and frictional strength of rock masses, undisturbed, or as affected by underground excavation. The effect of depth or stress *L7& P46
level, and anisotropic strength, structure and stress are each addressed, and practical solutions suggested. The paper concludes withan evaluation of the potential improvements in rock mass properties and reduced support needs that can be expected from state-ofthe-art pre-injection with fine, cementicious multi-grouts, based on measurements of permeability tensor principal value rotations <~s{&cL!%#
and reductions, caused by grout penetration of the least favourable joint sets. Several slightly improved Q-parameter ratings form moz *=a
the basis of the predicted improvements in general rock mass properties that can be achieved by pre-grouting. r 2002 Elsevier T)4pLN
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