Sealing of Boreholes and Underground Excavations in Rock
K. Fuenkajorn – Rock Engineering International, Tucson, USA
J. J. K. Daemen – Mining Engineering Department, University of Nevada, USA
Sealing of boreholes and underground excavations has not received much engineering attention until fairly recently. The growing awareness of and sensitivity to environmental concerns of the technical community as well as of the public at large has resulted in an increasing recognition of the fact that these geological penetrations may have an environmental impact. The issue of possible contamination resulting from migration along boreholes, adits, shafts or tunnels unquestionably has been raised most forcefully within the context of nuclear waste disposal. Several nuclear waste disposal programs, notably the Civilian and the Defence programs of the US Department of Energy, the US Nuclear Regulatory Commission and the Canadian and Swedish radioactive waste disposal programs have conducted major research efforts aimed at developing adequate seal designs for penetrations in host rock formations for high-level nuclear waste repositories. While a considerable data base has been gathered over the last two decades or so with regard to the performance of seals, most of the information is presented in research reports and widely scattered papers in journals and proceedings of conferences. Hence, the materials are not readily accessible to potential users such as designers, contractors or regulators who are not familiar with nuclear waste disposal programs. Although many government agencies have implemented regulations requiring that unused boreholes and underground excavations in rock formations be sealed, these regulations tend to be generic and broad, and rarely allow for taking into account site-specific conditions. As a result, it is probable that, for example, they are excessively conservative for some locations and inadequate for others.
Chapters 19 and 20 of this book, on instability around underground excavations, are direct analogues of Chapters 17 and 18, which were concerned with surface excavation instability. In this chapter, the underground instability mechanisms are presented. In Chapter 20, the design and analysis of underground excavations are discussed in the context of these mechanisms. In Section 16.2, the distinction between structurally-controlled and stresscontrolled instability mechanisms is explained. Accordingly, this chapter has been devoted to these two primary instability modes, considering also composite instability modes and the effect of time and weathering on excavation stability.
Fundamentals of Rock Mechanics
J. C. Jaeger, N. G. W. Cook, andR. W. Zimmerman
When the first edition of this book appeared in 1969, rock mechanics had
only recently begun to emerge as a distinct and identifiable scientific subject. It coalesced from several strands, including classical continuum mechanics, engineering andstructural geology, andmining engineering. The two senior authors of Fundamentals of Rock Mechanics were perhaps uniquely qualified to play seminal roles in bringing about this emergence. John Jaeger hadby that time already enjoyeda long anddistinguishedcareer as arguably the preeminent appliedmathematician of the English-speaking world, andwas the coauthor, with H. S. Carslaw, of one of the true classics of the scientific literature, Conduction of Heat in Solids. Neville Cook was at that time barely 30 years old, but was already the director of research at the South African Chamber of Mines, and well on his way to becoming acknowledged as the leading and most brilliant figure in this new fieldof rock mechanics.