The present book is the result of work carried out over a period of
about ten years by the author and his co-workers in order to describe
more accurately the slow irreversible deformation in time of the rocks
surrounding underground openings. To begin with, our efforts were
directed toward a better under- standing of the mechanical behaviour of
rocks and to the formulation of more precise mathematical models for
their dominant mechanical properties, mainly irreversible dilatancy
and/or compressibility during creep. Subsequent efforts were focused on
finding improved solutions to important mining and oil engineering
problems, such as, for instance, the creep of rocks around wells and
tunnels, short-term failure which may occur around an underground
opening, damage and failure which take place after long-time intervals,
the tunnel support analysis incorporating rock creep, etc. The book is
the result of a great number of questions posed either by mining
engineers or by the author himself, and of the corresponding answers
(unfor- tunately often only partial answers). This dialogue must
certainly be continued in order to improve the models and to formulate
models for other kinds of rocks, or, ultimately to obtain solutions for
other important engineering problems. It is hoped that the book will
also contribute to a better description, by means of mathematical
models, of the mechanical behaviour of rocks.
