The performance prediction of roadheaders from easy testing methods

An accurate prediction of roadheader performance helps to make for more efficient and cost effective planning of tunneling projects. In this study, the performance prediction models for roadheaders were developed by using easy testing methods such as Brazilian tensile strength, point load strength, block punch strength, ultrasonic velocity, density, porosity, and the water absorption ratio. A Dosco Mk-2B axial type roadheader has been monitored during roadway construction in an underground lignite mine located in Cayirhan, a town of Ankara and the instantaneous cutting rates (ICR) were calculated. Physical and mechanical tests were conducted on the rock samples collected from each observation location. Simple regression analysis showed that the physico-mechanical rock properties were not correlated with the ICR values. Stepwise multiple regression analysis was also performed, and the best model to predict the ICR of the roadheader was selected. The best model with a high correlation coefficient (r = 0.89) includes point load strength and water absorption by weight. The simple models including two variables were also developed for alternative use in practice. In addition, the usability of the derived models in a jointed rock mass was discussed by including a correction factor to the models for geological discontinuities. A concluding remark is that the derived models can be practically used for the estimation of the ICR of roadheaders in similar formations.