Use of the punch test for estimating TBM performance (Reprinted from Canadian Tunnelling, 1998)

This paper discusses the history of the punch test as a laboratory tool for estimating Raise Boring Machine and Tunnel Boring Machine penetration rates. Included are discussions of some of the methods that have been used to evaluate the test results for this purpose and how the test has been used to evaluate certain rock characteristics such as brittleness, bedding or cleavage, and porosity, which have been observed to affect machine performance. Also presented are some examples as to how the test has been used in an expanded form to evaluate the effect of certain machine parameters such as cutter spacing and geometry on excavation rates. Based on this, it is concluded that the punch test has proven itself to be a powerful laboratory tool far evaluating rock boreability and that it has the potential of becoming a stand alone test for this purpose. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.