Study on the Correlations Between Abrasiveness and Mechanical Properties of Rocks Combining with the Microstructure Characteristic

Excerpt

Rock abrasivity has become one of the necessary parameters for mechanical excavation of rock in the tunnelling industry (Wijk 1992; Hassanpour et al. 2011). The Cerchar abrasiveness test is widely used to assess the rock abrasivity. The test features a steel pin of specified shape and quality that is scratched over 10 mm of the specimen’s surface. The pin has a sharp conical point with cone angle of 90°. A static force of 70 N is loaded on the pin and the test is carried out by moving the steel pin at a prescribed velocity on the testing surface. The Cerchar abrasiveness index (CAI) is calculated by multiplying the mean value of the wear flats stated in units of 0.01 mm by 10. The testing velocity is reduced from 10 mm/s of “Cerchar apparatus” to 1 mm/s of “West apparatus” to accommodate the controllability of the testing velocity (West 1981, 1989; Michael et al. 2014). …