A model to predict the cutting performance of rapid excavation systems

This paper is a summary of a research work carried out within NATO TU-Excavation Project. The work consists of two parts. First an empirical model, based on the statistical analysis of large amount of in situ data collected from different roadheaders and impact hammers applications, is given in detail. This model gives an empirical relationship between the net advance cutting rates of the machines, and the rock mass cuttability index. The predicted values of cutting rates are later compared with actual values in different mining and civil engineering projects using roadheaders and impact hammers. The second part of the research work describes a model based on full scale cutting tests carried out in the laboratory with a linear cutting machine using real life cutting tools and the optimum specific energy values obtained for different RQD and s/p values are used to calculate the net cutting rate of a rapid excavation system. Two methods described above are compared in the paper and a general recommendation is made for a realistic approach.