To improve the wear resistance of disc cutters for tunnel boring machines (TBMs), this study is devoted to investigating the effects of rocks and cutter ring properties on the wear behaviors of disc cutters and the matching characteristics between the cutter ring properties and hard rocks. Cutter–rock wear tests were performed and the results show that the cutter ring properties and rock types significantly affect the cutter ring wear. The mass losses of cutter ring samples sliding against different types of hard rock are different and vary with the cutter ring properties because of the discrepancies in loads, vibrations, rock properties, and transition of the wear mechanisms. Finally, matching characteristics between the cutter ring properties and hard rocks are revealed.

The mud cake is easily formed during the tunnel boring machine (TBM) excavation in clay soils or rocks containing clay minerals. Mud cake will lead to soil disturbance of tunnel face, clogging cutterhead and even affect the construction efficiency and personnel safety. In this study, a discrimination method of mud cake formation based on cutterhead temperature was proposed. An online monitoring system was designed and installed on the slurry balance TBM. The results show that: (a) the cutterhead temperature data can be reliably detected and transmitted by the system; (b) in a tunneling cycle, the temperature at some positions of the cutterhead will increase first and then decrease; (c) during the field test, the temperature variation is around 2.5 °C under the normal condition, but the temperature variation will increase more than 50 °C due to the mud cake or geological change; (d) compared with the cooling rate, mud cake formation can be accurately discriminated.

To investigate wear characteristics of tunnel boring machine (TBM) disc cutter rings interacting with types of rock, a range of wear tests were performed on a TBM cutter test rig, and laboratory-scale disc cutters were used in the experiments. The mass loss, vertical load, temperature field, wear mechanism and change rule of cutter tip for the disc cutter rings were obtained during the tests. The results indicate that the rock types and properties of rock exhibit great influences on the cutter wear. The variation of the weight loss testing with different types of rock is partially explained by the discrepancies of vertical load, cutting temperature, and the transition of wear mechanisms. In addition, the test results show that the wear characteristics of cutter rings are mainly affected by uniaxial compressive strength (UCS) rather than equivalent quartz content (EQC) for types of rock. This study will benefit the design of cutter rings with enhanced wear resistance.

Rock cutting methods for disc cutters with coupled static–dynamic loads and static loads are explored and compared through rock breaking experiments to improve the TBM excavation efficiency. Results indicate that the rock breaking characteristics, including rock debris, cutting force, and rock breaking efficiency, significantly varies with different cutting methods. The average size of rock fragmentation produced under coupled static–dynamic loads is 1.6 times larger than that under static loads. The cutting forces of disc cutter under the coupled static–dynamic loads are larger than those under static loads when the cutting depth (h) is lower than 4 mm, whereas is contrary when h exceeds 4 mm. The specific energy of disc cutter under the coupled static–dynamic load is approximately 1.5 times smaller than that under the static load, indicating the cutting method with the coupled static–dynamic load can significantly improve the cutting performance. There is an optimal cutter spacing (S) for the cutter under each cutting method. The optimal S under the coupled static–dynamic loads is larger than that with static loads. This study provides new insights into improving the tunneling efficiency in high-strength rock conditions.