Dynamic Response Analysis Of The Cutter Head System Of The Full Face Rock Tunnel Boring Machine

In modern underground tunnel construction,Tunnel Boring Machine(TBM)has been more widely used,for its high degree of automation,security and efficiency.Cutter head and disc cutters constitute the cutter head system,which is important for TBM.During construction,the TBM cutter head system has a bad working environment and a complicated loading condition,and can produce various forms of vibration.So the study of dynamic responses of the TBM cutter head has a great engineering significance for performance prediction.1.The vibration of cutter head system,in general,can be seen as a thin circular plate vibration system under multiple time related concentrated loads.In this paper,according to the vibration theory of elasticity,the natural frequency and mode of the thin circular plate are obtained.Forced vibrations of circular plate under single and multiple time-related concentrated loads are analysised.2.The modal analysis of TBM cutter head system is done by using ANSYS software.The integral modes which involve the majority bending deformation of the panel are obtained.And the local modes which only involve the rib plates of cutter head system are obtained.We do a comparative analysis between the integral modes of cutter head system and the theoretical modes of thin circular plates.And natural frequencies of each order of the cutter head system are obtained,which provides the basis for the prevention of low-frequency resonance.3.The starting process of cutter system are transient dynamic analysised,and we get the displacement-time curve and velocity-time curve of cutter system during the starting process.We plot the transient response curves of three different disc cutters which are center disc cutter,normal disc cutter and edge disc cutter,when the cutting depth is 5mm,11 mm and 17 mm.In addition,the dynamic response of the cutter head system is analyzed in the same depth while cutting rock with different hardness.The influence of the change of system damping during vibration is explored.The results show that deformation peaks of the cutter head system's vibration are decreased with the increase of system damping,and the starting process is more stable.These results provide theoretical basises for selecting the optimal cutting depth in the construction process.4.Through the steady-state analysis of TBM cutter disc system,we can get the response curve,which are displacement-time curve and speed-time curve of each location hob,when TBM in stable operation.The effect of damping is analyzed.The results show that with the increase of system damping,the peak of vibration deformation decreases,but little change in the mean displacement.