I.W. Farmer – författare

Rock masses comprise systems of discontinuities developed by tectonic action or diagenesis, and occasionally imposed by excavation, which bound blocks of intact rock. Fluid flow is determined by distribution of the discontinuities and by the way in which their apertures respond to natural and imposed stress fields in the rock masses. This book develops simple usable fracture flow models based on an understanding of discontinuity structures and on the mechanics of rock and discontinuity deformation, incorporating these into simple models derived from percolation theory. Using these models, the reader is able to analyze and predict fluid flow through rock for hydrological problems and also for the design of underground structures where inflow is a problem.

'Engineering geology' is one of those terms that invite definition. The American Geological Institute, for example, has expanded the term to mean 'the application of the geological sciences to engineering practice for the purpose of assuring that the geological factors affecting the location, design, construction, operation and mainten­ ance of engineering works are recognized and adequately provided for'. It has also been defined by W. R. Judd in the McGraw-Hill Encyclopaedia of Science and Technology as 'the application of education and experience in geology and other geosciences to solve geological problems posed by civil engineering structures'. Judd goes on to specify those branches of the geological or geo-sciences as surface (or surficial) geology, structural/fabric geology, geohydro­ logy, geophysics, soil and rock mechanics. Soil mechanics is firmly included as a geological science in spite of the perhaps rather unfortunate trends over the years (now happily being reversed) towards purely mechanistic analyses which may well provide acceptable solutions for only the simplest geology. Many subjects evolve through their subject areas from an interdisciplinary background and it is just such instances that pose the greatest difficulties of definition. Since the form of educational development experienced by the practitioners of the subject ulti­ mately bears quite strongly upon the corporate concept of the term 'engineering geology', it is useful briefly to consider that educational background.

The first edition of this book was received more kindly than it deserved by some, and with some scepticism by others. It set out to present a simple, concise and reasonably comprehensive introduction to some of the theoretical and empirical criteria which may be used to define rock as a structural material. The objectives - reinforced by the change in title - remain the same, but the approach has been changed considerably and only one or two sections have been retained from the first edition. The particular aim in this edition is to provide a description of the mechanical behaviour of rocks, based firmly upon experimental data, which can be used to explain how rocks deform, fracture and yield, and to show how this knowledge can be used in design. The major emphasis is on the behaviour of rocks as materials, although in the later chapters the behaviour of discontinuities in rocks, and the way in of rock masses, is considered. which this can affect the behaviour If this edition is an improvement on the first edition it reflects the debt lowe to numerous people who have attempted to explain the rudiments of the subject to me. I should like to thank Peter Attewell and Roy Scott in particular. I should also like to thank Tony Price and Mike Gilbert whose work at Newcastle I have used shamelessly.