The Research On Interaction Rules Of Shield Cutter Head With Ground

Earth pressure balance shield machine is a important technical equipment in the tunnnel construction of national infrastructure.Cutterhead is an important component of shield machine and it plays a major role to break rock and allow the soil to cross through and support the tunneling interfaceStudy of movement rules of the soil in the cutterhead system and the dynamic loads of cutterhead system have important theoretical and realistic significance to reveal the laws of the interaction of cutterhead and rock, designing and optimizing the structure of cutterhead. Funded by the national natural science fund project,The main content of the paper "Study of laws of interaction of cutterhead and rock,and the design theory of cutterhead system(E51105048)" is as follows:(1) Take the Earth pressure balance shield machine as research object, Establish the discrete element simulation geometric model of cutterhead tunneling system with discrete element software PFC3 D.Exerting the corresponding load boundary conditions and working parameters, according to the working principle of the shield cutterhead system tunneling,which Laies a foundation for further simulation analysis.(2) Take the spoke cutterhead as example, obtain the cutterhead thrus and cutterhead torque by running the model. Compare the torque value and thrus value of simulation to the torque value of theoretical calculation, then verify the rationality of the simulation model from two aspects. Changing the cutterhead rotation, the displacements of soil particles in front of the cutterhead, in the cutterhead and in the chamber at different time are displayed respectively. It comes to a conclusion that the soil movement show the periodic change rule.The movement period is related to cutterhead rotation.(3) Changing the cutterhead opening style, then select the particle group in the front of the cutterhead for tracking the flowing of the soil particle. The particle going through ratio is67% for spoke cutterhead and 33% for board cutterhead, the spoke cutterhead is better than the board cutterhead, and make analysis of clapboard pressure and cutters positive pressure.The simulaltion results illustrates that it is necessary to improve the center structure of the spoke cutterhead, decrease the friction between the board and the soils, and adjust the amounting angle of the cutter to improve the flow of particles.(4) On the basic parameters of simulation model, individually adjust contact stiffness and friction coefficient of particles and cutterhead rotation, advance speed and screw conveyor rotation of shield machine, to research the influence of changing parameters on macro excavating performance indicator, for example, cutterhead torque, cutterhead thrust and chamber pressure. This can provide theoretical basis for design of shield machine cutterhead system structure and selection of operation parameters.