Effect of Cone Indenter Hardness on Specific Energy of Rock Cutting

Abstract

The effects of rock mechanics parameters on performance of various tunneling and excavation machines used in tunneling application has been an important issue in conventional, NATM, and TBM tunneling. Mechanical feature of machine performance is important for cutting specific energy and cutting parameters. Specific Energy (SE) of rock excavation depends on rock features such as uniaxial compressive strength (UCS), Brazilian tensile strength (BTS) and standard cone indenter hardness (Is), as well as bit shape and size, cutterhead design, and cut geometry. In this study, impact of cone indenter hardness on SE has been examined and results of statistical analysis on laboratory data related to linear scale cutting of various rock types with different pick cutters are discussed. The results shows that there is a strong relationship between cone indenter hardness and laboratory specific energy. The cone indenter hardness results are between 0.30 MPa and 3.63 MPa. The tests were applied on weak and moderate rocks types. Based on the test results, two different prediction models were created using second order functional regression analyses.