Experimental study on the influence of cutter shape on cutter wear for hard rocks

Abstract

Cutter shape is an important factor on cutter wear for hard rock TBMs. In this paper, the influence of cutter shape on the cutter wear was investigated by the wear tests on small-size cutters with the scale of 1/10 of the actual size, and the related rock fragmentation characteristics induced by different cutters was studied as well. In the tests, 6 types of small-size cutters, considering the design parameters of cutter diameter, cutter tip width and cutter tip shape, were selected. The granite samples were collected from the Beishan site, Gansu province of China. For each test, the cutting distance of the single cutter was 100m, and then the cutter wear could be obtained by weighing method. The tests shown that, 1) the cutter wear was basically proportional to the cutter tip width when the same penetration was reached, while the cutter force was not reduced remarkably for the narrow cutter when compared with that of wide-tip cutter; 2) the wear of 17-inch cutter was much higher when compared with that of 19-in and 20-in cutters; 3) the wear of round-edged cutter was obviously lower than that of flat-edged cutter, due to the former hardly presented curling behaviour after cutting while the latter had obviously curled. The test results facilitated better understanding of wear mechanism of TBM cutters and provided the references for cutter selection for TBM tunnelling in hard rock.