Rock Grouting: With Emphasis on Dam Sites

This book contains a wealth of data on grouting programmes for specific projects including information about quantities of grout injected, with pressure tests before and after grouting and examination of drill cores after grouting. Grouting at eight sites is considered in detail; six of the sites are dams, of the other two, one is for an underground garage, the other for the foundations of a bridge. There are lengthy sections on water pressure test, hydraulic fracture and grout penetration, especially by bed separation (called 'tearing' in the book), with numerous examples. An important omission, which spoils the balance of the book, is general absence of reference to the grout mixes used. In one or two cases, the water/cement ratio is given and it is generally inferred that the grout mixes used are 'thick'. Only by detective work and inference can it be determined that the sole grout injections considered are of cement and water with, in two cases, the addition of bentonite and, in one case, an oblique reference to the addition of sand. In common with many other engineers, the author appears to think (erroneously) that 'grouting' means only the injection of cement and water, probably with small additions of some other material such as bentonite. His confusion over grouting is highlighted by the statement in the Introduction that 'Grouting of soils is, above all, understood as "chemical g r o u t i n g " . . . ' which will be a startling revelation to engineers and contractors who have been concerned with alluvial grouting for the past 50 years. Perhaps most astonishing of all is the absence of any reference to A. Casgrande's classic Rankine Lecture on seepage control through dam foundations, covering grouting and drainage, delivered in 1961. Finally, the book concludes with 'an attempt at guide-lines'. Like parts of the rest of the book, these are made difficult to understand by the poor quality of the translation. A sentence like 'But if there exists an alteration of the bedding or banks of different permeabilities, then it becomes questionable whether results or permeability tests in reality reflect the overall permeability of a larger section of the rock mass, such as, for instance, between the upstream and downstream side of the dam' has its meaning shining dimly through the fog of words, but only dimly.