Papers by Author: Bulent Tiryaki

Abstract: The selection of the cutter type is of crucial importance to maximise the advantages of mechanical rock excavation systems. Specific energy (SE), cutter forces, and rock properties are used to decide what type of cutter is most suitable for economical excavation of the rock based on laboratory rock cutting tests. This study is concerned with the preliminary results of an ongoing rock cutting program in which a mini-disc has been compared with a point-attack pick in laboratory linear cutting tests simulating a cutterhead on a Helidon sandstone block. Analysis of the preliminary results has shown that the mini-disc experienced lower mean cutting forces and was seven times more efficient than the pick in first layer cuts. However, the mini-disc had mean normal forces 1.5 times higher than the pick. Additionally, first layer cuts taken on the trimmed surfaces required more forces and SE than completely relieved cuts in pick cutting.

Abstract: Rock cuttability is expressed by specific energy (SE) that is defined as the energy required for cutting unit volume of rock. Direct determination of SE requires a rock cutting rig and is expensive and time-consuming. Therefore, empirical models have been alternative methods for predicting SE from rock properties. Two different predictive models of SE have been developed in this study using regression tree and artificial neural network (ANN) methods. Both empirical models employed the uniaxial compressive strength (UCS) and Mode I fracture toughness (KIC), being derived from tensile strength (t), as predictors. Data from four different studies have been used to develop the models. Statistical analyses on the data set have shown that both UCS and KIC are closely related to SE in a nonlinear form. Numerical and graphical measures of the goodness of the fit and ANOVA test have shown that regression tree and ANN models have performed similarly.