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It has been found that the impact performance of water jets can be changed by its properties, which include pressure, additive, and mode of jet. Thus, an abrasive water jet (AWJ) has been developed as a new method. However, there is little research on the effect of abrasive concentration on the impact performance of abrasive jets. Thus, the SPH method is used to establish an abrasive water jet crushing concrete model to study the effect of abrasive concentration on the impact force, concrete internal energy, abrasive particle distribution, crushing depth, and damage and crushing efficiencies under different concrete compressive strengths and abrasive densities. The results indicate that there is little effect of the abrasive concentration on the peak impact force under different compressive strengths and abrasive densities, while the mean impact force tends to increase linearly with the abrasive concentration. The internal energy of the concrete increases stepwise with the abrasive concentration under different compressive strengths and abrasive densities. The concentration of 10%∼20% is the rapid increasing stage. The crushing depth and damage efficiencies are all maximum at a concentration of 20% under different compressive strengths and abrasive densities. After the concrete was impacted by the water from the water jet, it is divided into rebounding particles and intrusive particles. The more the intrusive particles, the easier the concrete to be crushed and damaged.

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Abstract：The consumption of disc cutters on full-face rock tunnel boring machines (TBMs) accounts for a large percentage of the tunnel excavation cost. Based on the engineering data from Qinling rock tunnel in China and Røssåga rock tunnel in Norway, the wear mechanism of disc cutters has been studied with an energy approach. The unit friction work of cutter rings and an equavilent wear function are proposed and analyzed. The calculation formula of the cutter ring unit friction work is established according to the rock breaking loads, cutter position parameters and TBM boring parameters by analyzing the movement, load and wear mechanism of disc cutters on different cutter positions. Based on the solvement of the equivalent wear function and the calculation of the cutter ring unit friction work for the 8.8 m and 7.23 m diameter TBMs respectively, the wear of cutters on different cutterhead zones for TBMs boring through tunnel sections with different geology parameters is analyzed. It is found that the equivalent wear function is inversely proportional to the cutter life index (CLI). The symmetry axis of the equavilent wear function is determined by the disc cutter layout. The rock breaking and cutter wear status of the cutters around the symmetry axis is the best. By revealing the reasons for high wear rate of the cutters on inner and outer cutterhead zones, suggestions for cutter layout design are given, e.g. increasing the spacing of cutters in inner cutterhead zones, add more gage cutters with the tilt angle between 30º to 40º.Key words：tunnel boring machine；cutter wear；energy analysis；equavilent wear function 0 前言 *