Theoretical and experimental study of tunnel boring machine dynamic cutting force

Dynamic information about the cutter force, such as peak load, growth rate and frequency, is critical to maintaining the stability of the tunnel boring machine system and controlling cutterhead vibration. The current cutting force prediction formula cannot meet the solutions of the thrust and vibration of the cutterhead. Based on the idea of discrete modeling, the one-dimensional penetration of the traditional cavity expansion theory is extended to high-dimensional rotary rock test. The influence of rock mass parameters and operating parameters on the force is studied. And the full-scale rotary cutting test is used to verify the theory. The results show that the increases in installation radius, speed and penetration cause an increase in the volume of rock mass extruded by the cutter, and an acceleration in the boundary velocity of the core. It contributes to increase in the growth rate of cutter force and frequency of the cutterhead vibration. The higher strength of the rock mass leads to higher force peak value, growth rates and lower frequencies. The dynamic cutting force model differs from the test results within 5%, indicating the accuracy of the model.