Rock property testing for the assessment of tunnelling machine performance : McFeat-Smith, I Tunn Tunnlg, V9, N2, 1977, P29–33

Abstract

As part of a research project designed to develop criteria for the prediction of cutting performance of rock tunnelling equipment, tests were developed to identify rock properties which influence its cutting properties. Rock hardness indentation measuring tests were performed using an NCB cone indenter. A range of hardness measurements covering a number of common sedimentary rock types is shown against varying cutting and wear rates. Rebound hardness scleroscope measurements are similarly shown to be an important factor in the wear rate of drag-pick tools. A further aspect of the cutting properties of rock is the extent to which micro-bedding planes act as planes of weakness. A relative measure of the intensity of these planes can be obtained from wave velocity measurements. It is concluded that the tests show how rock properties can be applied to give an understanding of rock behaviour when being excavated. /TRRL/