Experimental Study on Rock Fragmentation by the 19-inch TBM Cutter and Statistical Analysis of Debris

The inspiration of this paper stems from the increasingly wide use of 19-inch disc cutters in recent TBM tunnel projects. The cutting mechanism of the 19-inch cutter is different from that of the 17-inch cutter. To explore the working performance of 19-inch cutter, a series of preliminary full-scale disc cutting tests are conducted with a single disc cutter (483mm diameter and 13mm tip width). This cutter was installed on the TJ-TS500 linear cutting machine (LCM), and a concrete specimen with a size of 980mm×980mm×500mm was cast in the model box. A database composed of specimen properties, cutter forces (normal, rolling and side), penetration depth, and spacing is established using the data collected from the LCM. Both normal and rolling force will increase with the increase of spacing, as well as penetration. Specific energy is a significant parameter in TBM performance predicting. The result shows that the lowest SE is not only correlated with spacing, but also penetration. The weight and size of chip debris are measured after one group of tests. Characteristics of chip debris are somewhat correlated with cutting process. SE and chip percentage have a rough negative correlation. Nominal size increases with spacing, especially for the largest chip debris. The results of the model test are valuable for the performance prediction of the field TBM.