Build. Sci. Vol. 8, pp. 93-96. Pergamon Press 1973. Printed in Great Britain
Rock Mechanics and Engineering CHARLES J A E G E R Cambridge University Press, 417 pp., £10.50
THIS A U T H O R I T A T I V E text constitutes a valuable collection of scientific and practical information for civil engineers. Following a brief introduction to rock materials and engineering geology, the physical and mechanical properties and test methods both of laboratory specimens and rock in situ are treated, with examples of numerical data. The properties include elasticity, tension, compression and shear strength, residual stresses, creep and permeability. Account is taken of both the pressure of water in pores and fissures and its physical and chemical effects. Examples are given of the use of elastic theory for intact, stratified and fissured rock, with a brief reference to the finite element technique. Rock mechanics is concerned with discontinuous strata and the author claims that this makes the subject more complex than soil mechanics. Nevertheless a great deal of the scientific basis for the testing and analysis of rock materials is similar and the reader with a good grounding in soil mechanics will find the text easier to follow. A third part devoted to slope stability, tunnels, cavities and dams is supported by practical examples of rock bolting and prestressing. Mechanical solutions are necessarily limited to simple structural arrangements and the problem remains of the choice of numerical parameters where irregular rock joints occur. A few mathematical errors are evident and there is a criticism of Casagrande's Rankine lecture
which seems somewhat inappropriate for a textbook bearing in mind that Casagrande reported valuable field observations, The book is completed with an important series of case histories, including detailed treatment of the Malpasset and Vajont dam disasters. A central feature of the Malpasset foundation movement is shown to be the influence of the applied stress changes on the rock permeability and therefore on water uplift and stability. The analysis of the Vajont Slide illustrates the complexity of formulating the analytical model from prior field explorations and highlights the importance of progressive failure. The reader will note that the phenomena of permeability variation with effective stress and also of progressive failure are important features of soil mechanics as is also the fact that disasters arise more from the incorrect formulation of the nature of the problem than from the incorrect measurement of material properties. The book is very well presented and illustrated and includes over 500 references and tabular data. It provides a good guide to the questions an engineer should raise and to the investigation procedures currently available. P. W. ROWE
Simon Engineering Laboratories, The University of Manchester.