Drilling and blasting is the most common and economic technique of rock
excavation from the earliest days of invention of explosives to these
days of modernisation. Although there have been significant developments
in blasting, application of this technology for rock excavation induces
damage to the remaining rock mass. The rock mass damage problem will
increase manifold if the blast loading is applied repeatedly as compared
to single episode blast rounds. The damage can easily extend a few
meters into the rock mass and the deteriorated rock mass can give rise
to serious support design problems in tunnels and caverns. This book
deals with the quantification of blast damage as a function of rock mass
quality (Q), which can be used for assessment of damage levels, in case
of repeated exposures of vibrations. A correlation between damage and
shear wave velocity was also established. The book also illustrates the
effect of joint orientations on blast damage to enhance the safety and
stability of underground excavations.