Dynamic Characteristic And New Structure Studies On TBM Disc Cutter Under Intensive Impact Loads

Since the beginning of21st century, the utilizations of underground space have got greatly attention, and TBM (Full Face Rock Tunnel Boring Machine)has become the first choose of hard rock tunnel equipment as its advantage in effective, safety, green, and have a broader market outlook. The disc cutters, as the key load-carry component, are the most vulnerable parts due to strong shock and vibration, which is directly affected on the efficiency and the construction cost of the TBM construction process. So, be considered in the traditional disc cutter design theory and vibration studies, the structure design of new type disc cutter supporting with sliding bearing is very necessary in order to improve vibration resistance, which is a great engineering significance and new direction of the disc cutter design. The paper comes from the topic "973", which is the sub-project of the Dynamic Behavior and Design Theory of Hard Rock Cutter Head System (973Program).The main work and content can describe as following.Firstly, according to the characteristics of disc cutter rock crushing, considering Characteristics of rock, disc cutter layout, performance parameters and cutter breaking rock, it is established a three-load conversion calculations the load of disc cutter time history simulation method. The center, normal and side disc cutter time course load are obtained, through Ansys/Ls-dyna simulation analysis. The loads of disc cutter are analyzed through time domain and frequency domain in details, which provide the excitation for dynamics analysis of the disc cutter system.Secondly, the dynamics model of the disc cutter system coupling bending-axial-swing is established after comprehensive considering the factors associated with the time-varying nonlinear bearing contact load, supporting stiffness, damping and other factors. The differential equations of the system are derived by analyzing the relative displacement relationship between each component. Meanwhile, the parameters in the equations are analyzed in details.Thirdly, the analysis of the natural vibration characteristics and dynamic response of the vibration system are analyzed. So the each order natural frequency of the disc cutter system and its corresponding vibration patterns is obtained. Further the dynamic response of the vibration system is analyzed under the combined effect of internal and external incentives, and the dynamic response of different types of disc cutter system through comparing each other is also obtained, Including the vibration displacement response, acceleration response, bearing the deformation and load distribution and the cutter shaft dynamic load。 At then the effect of lateral load factor on the dynamic responses of the system is analyzed.Fourthly, based on the process of time-varying loading about cutter bearing roller, the contact fatigue life of cutter bearing is calculated, and the modification design of cutter bearing roller is made by ANSYS. These tasks can eliminate the roller raceway contact edge stress concentration, improve the bearing load distribution and improve the contact fatigue life of disc cutter bearing.Finally, the new structure of TBM disc cutter based on the slide support is designed, which will improve the vibration resistance reducing the damage of disc cutter. Then it is analyzed separately from the design, fabrication and performance evaluation for new type disc cutter, providing a reference for the design of new production.