ABSTRACT:
Rock mass classification has come to be associated with the selection of a rock mass quality class on the basis of prior classification or rating of various rock mass parameters. The presence of a tunnel or slope or similar is implied, and the disturbance to local rock mass characteristics, caused by the excavation disturbed zone, is supposed to be captured in the local rock class, as support will be chosen. Rock mass characterization reflects a broader mission to describe the character of a rock mass where a future project is likely to be realized, but no excavation presently exists, except of borehole scale. In this paper, cross-disciplinary examples of rock mass classification and characterization are selected from various civil engineering construction projects, making much use of seismic velocity for emphasizing the links between rock quality, deformability, permeability and velocity, and for helping to distinguish between classification and characterization. However these terms obviously overlap in common usage.
1 INTRODUCTION
Rock mass classification has come to be associated with the need to select a rock mass class on the basis of prior classification or rating of various rock mass parameters. It may also reflect a need for pretreatment. Implicit here is the existence of the tunnel, and the effect this may have on the expected rock mass response, in particular that within the EDZ. All of the above may also apply to rock slopes, but here post-treatment is more likely. Rock mass characterization reflects a broader mission to describe the character of a rock mass where a future project is likely to be realized. Besides rock quality description with one or more of the standard measures (e.g. RQD, RMR, Q or GSI), it should also include site characterization fundamentals such as rock stress, water pressure, permeability and seismic velocities.
