Research on natural frequency characteristics of thrust system for EPB machines

The objective of this project is to investigate natural characteristics of thrust system. We found that with different arrangement and various extension of hydraulic cylinder, the stiffness of cylinder could be reduced. On one hand, based on the second form of Lagrange equation, we developed one vibration model for driving system. Through the eigenvalue theory of matrix analysis, we discovered the frequency line of the thrust system. On the other hand, by applying frequency lines to analyze the thrust systems of shield machine in engineering applications, features of natural frequencies in several systems with various arrangements have been discussed in detail. Case study shows that to prevent resonance, the avoiding band of the natural frequencies in even systems is much narrower than the one in uneven systems. The result provides a theoretical foundation and guideline for the design of thrust systems in shield tunneling machines.