Roadheader excavation performance-Geological and geotechnical influences

The prediction of tunnel stability usually is the main subject in geotechnical site investigations prior to tunnelling projects. During the last few years in mechanical excavation, problems have occured also connected with the accurate prediction of excavation performance and tool wear in soft and hard rock. Every now and again problems have been encountered leading to high bit consumption and low cutting performance of roadheaders. In this paper the connection between some geological features, cutting performance and bit wear is presented. Further, some major correlations of specific rock properties as well as geological factors with measured bit wear and excavation rates are shown.