Multi-directional coupling dynamic characteristics analysis of TBM cutterhead system based on tunnelling field test

Abstract

The core component, TBM cutterhead, bears a multi-directional impact load because of its direct contact with rock during tunneling. Unreasonable cutter design and parameter set lead to severe vibration or abnormal injury during excavation, seriously affecting the efficiency of the TBM tunneling. Therefore, study of cutterhead dynamics response under impact loads is one of the core content of TBM system design. TBM multi-degree-of-freedom coupled dynamic model contains different geological conditions, cutter speed, body mass, time-varying mesh stiffness, transmission error, etc. A method is proposed to solve the problem based on Newmark algorithm, which further improves the solution efficiency. A tunneling field test was conducted, and the results verify the correctness of the model and the simplified cutter system. The simulation results of the Dahuofang project show that: ➀ The calculation process of Newmark is simplified, the calculation speed increased 3-4 orders of magnitude higher than Runge-Kutta method, while the solving time was reduced from 2.6e5 s to 155 s under the same precision; ➁ Compared with the results of two kinds of rock with compressive strength 150 MPa and 95 MPa, the translational vibration amplitude ratio is 3.33 and axial vibration amplitude ratio is 2.08. It indicates that as the rock compressive strength increases, the growth of the cutterhead’s vibration amplitude increase accelerated, rather than proportional increases; ➂ The vibration decreases along with the cutter speed becomes larger and the system becomes stabilized when the cutterhead speed turns into 4r/min. The cutter head speed clearly affects torsional, lateral and longitudinal vibration. The change rate has reached 0.53-0.61. Therefore, TBM should choose the right cutter speed to avoid bearing damage, seal failure and other serious accidents; 4 The translational vibration of components decreases with the components’ mass increase. It has the greatest impact on the horizontal and vertical vibration of the big ring. The vibration changing rate of the big ring reaches 0.31. The big ring has almost no effect on the axial vibration and overturn, but the energy consumed on rock cutting will be reduced as the mass increases. Body weight should be chosen reasonably considering vibration,construction economy and internal excitation of parameters. The above conclusions provide a theoretical basis for TBM dynamics optimization design, vibration control and cutterhead architecture design.