Engineering geology and rock mechanics are applied sciences, the final object of which is to assist in solving practical engineering problems. How they do this is best illustrated by case histories. Some of them have already been discussed in the chapters on engineering geology and rock mechanics; others have been mentioned in the three chapters on rock slopes, galleries, tunnels and excavations and on dam foundations. A few additional cases of special interest have been selected to illustrate the many very different lines of approach vital to design problems; each case stresses a few special points.

Chapter 12 examines cases concerning dam foundations and underground works of American design. Additional information is given about tunnel design and testing. Chapters 13 and 14 describe the two most dramatic failures of large engineering structures in recent times, that of the Malpasset dam and the rock slide at Vajont. Chapters 15 and 16 concern the consolidation of difficult rock slopes and the construction of three large underground power-stations. These five chapters supplement chapters 5 to 11.