A Theoretical and Experimental Study of Tunnel Boring by Machine with an Emphasis on Boreability Prediction and Machine Design

摘要

The report discusses the results of the first 12 months of a proposed 3-year research effort. The ultimate goal of this project was to develop scaling relationships required to predict field-boring performance from tests performed on small cores from along the proposed tunnel line. Fundamentals of failure of hard rock under cutters of various shapes and sizes were studied by performing both small-scale and full-size linear cutter tests. Average horizontal and vertical forces, actual penetration, specific energy, cutting coefficient and cutting size distribution were calculated, through the use of an analog-digital computer, from the results of laboratory experiments using a small linear cutter on rock samples from the Nast, Lawrence, and Climax Tunnels. The results of that testing are presented. A large linear cutting machine, capable of being operated either at a constant force or a constant penetrating mode has been designed and constructed. (Modified author abstract)