Numerical Simulation And Experimental Study Of Rock Fragmentation Characteristic By TBM Disc Cutters

The Tunnel Boring Machine (TBM) is the important technic equipment while lacking research in China. It is widely used in the underground engineering constructions. As a key component of breaking and stripping rock in the tunneling process, the crushing efficiency and load of disc cutter directly impact on the progress and cost of construction. Accessed to a large number of domestic and international literature, based on the analysis of the disc cutter and rock interaction mechanism, this paper makes an in-depth research on the cutting efficiency of TBM disc cutters with different combination of parameters. The main contents are as follows:(1) Based on the relieved cutting mode and unrelieved cutting mode, the method of calculating the volume of broken rock is deduced, and it leads to the proposal of the methods to determine the optimum cutter spacing corresponding to the minimum energy consumption. And then, the accuracy and feasibility of the theoretical method is verified by the engineering application.(2) The numerical model of the interaction between the disc cutter and rock mass has been established using the method of particle discrete element. Then the crack evolution of different joints characteristics is obtained. What’s more, rock fragmentation patterns, rock fragment size and crushing efficiency have been discussed. Thus, the dynamic response mechanism of the rock mass under the action of disc cutter has been revealed from the mesoscopic view.(3) In the finite element environment, the model of TBM disc cutters has been established. The dynamic simulation of the cutting process of different kinds of cutter arrangement is studied. Through the accurate simulation, the cutter spacing, penetration depth and cutting speed that impact the cutting efficiency are analyzed. Then, by using the orthogonal test, the coupling impact of the factors on the cutting performance is analyzed. Furthermore, the influence of single factor and the best combination of factors to the comprehensive evaluation is obtained.(4) Using the rotary tool cutting test platform, researches on disc cutters crushing and rock cutting process have been made respectively. The macro destruction phenomenon of rock induced by the disc cutter has been analyzed. The optimum cutter spacing under different penetration depths have been obtained. The experimental results convincingly demonstrate that the numerical simulation is correct and feasible.