Twenty-Five Years Of Rock Mechanics - A Personal View

Although the term 'rock mechanics' started to become popular about the time of the First U.S. Rook Mechanics Symposium in 1956, study of the mechanical behavior of rock certainly pre-dates this event. Bucky, Phillips, Von Karman, Fayol, Galileo...the list of significant contributors can be traced back over centuries, - not surprising for the oldest structural material used by man. Started with a strong mining orientation by the Colorado School of Mines, University of Minnesota, and Pennsylvania State University, joined soon after by Missouri School of Mines and the University of Texas, the Annual U.S. Symposium on Bock Mechanics has evolved into the main U.S. form for discussion of all aspects of rock mechanics, basic and applied - tectonophysics to comminution; near-surf ace foundations to deep mine support design. Although dominantly a U.S. event the annual symposium has benefitted from regular and important contributions from abroad. It would be presumptuous to attempt a comprehensive statement of significant developments over the 25-year history of the U.S. Bock Mechanics Symposium. This anniversary address will attempt instead to present a personal view of developments that appear to be of broad general significance and that may indicate directions for the future. Among the developments to be discussed in the address arc the following: - Energy Basis of Book Fracture Early rock mechanics investigators often overlooked the important distinction between a failure initiation stress and structural collapse. Although essentially synonymous in the