Digital Simulation Research On Gripping-Thrust-Regripping Mechanical-Hydraulic System In Tunnel Boring Machine

In this dissertation, a national high-tech R&D program(863 Program) 'research on the large diameter full-face tunnel boring equipment and engineering machinery' and a national key basic R&D program(973 Program) 'key basic problems of hard rock tunneling equipment' are studied. The mechanical and hydraulic model of TBM's 'gripping-thrust-regripping' system are modeled and analyzed on the purpose of studying its characteristics. The precise and specific digital model of deviation correcting system, propelling system and so on are also built and analyzed.Based on the specific introduction of the main system, especially the gripping-thrust-regripping system, the main working procedure and the forms of motion of the components are defined. Then the hydraulic system is built. The 'four connected cylinder' structure of propelling system and its strong hydraulic-mechanical coupling character are also defined, which lays a foundation for the modeling and analysis work.A co-simulation approach is used in order to solve the multisystem coupling problem. The mechanical model and the hydraulic model of the propelling system are established. After the configuration of the software interface settings and the boundary conditions of surrounding rock, the dynamic behavior of the coupling system is analyzed. The dynamic response of the deviation correcting system under partial load during normal excavation is simulated. Especially, the influence of load form and fluctuation frequency, the pump and other hydraulic components parameters and the stroke of propelling cylinder are analyzed. A performance evaluation index called deviation correction rate is also defined.Aiming at the important design objective 'high-stiffness', the FEA model of the components is built to analyze the stiffness of the system. The variation trend and the stiffness contribution of the different components are studied. Especially, the equivalent stiffness of the hydraulic system is calculated and built into the model. The vulnerable spot of the system stiffness is found out and some solutions are brought in to improve it.The characteristic of TBM's propelling system is studied by the digital simulation method. A series of vital conclusions and laws are brought out which provide a firm technical support on the setting up for the test bed, the development & production of prototype and its productization.