Study On The Jam Breakout Technology Of Tunnel Boring Machine Cutterhead Driving System Based On Hydro-viscous Coupling Mechanism

Tunnel Boring Machine (referred to as TBM) is a large factory tunnel construction equipment, which combines the rock mechanics, mechanical engineering, electrical science, hydraulic technology, optical measurement, tunnel engineering, etc. together. It is mainly composed of a propulsion system, cutter system, support and change mechanism, guidance system, and auxiliary equipment etc. Due to the hostile tunnel environment and characteristics change of surrounding rock, TBM often get trapped during the tunneling process. Because the driving torque of cutter system is not sufficiently large, manual method is used to get the TBM out of jam, which causes problems such as excessive economic and time cost, potentially dangerous, etc. So it is very important for efficient tunneling to improve the torque performance of cutter driving system, and establish jam breakout technology for TBM.In order to improve the torque performance, a new driving scheme using variable-frequency motor, flywheel and Hydro-viscous clutch (referred to as HVC) was designed without additional installed power increase to TBM cutter head driving system. The key point of new scheme is how to effectively and reasonably control HVC. Since the dynamic process of jam breakout brings new challenges of control accuracy、slip loss、dynamic response speed to HVC, therefore, it is an inevitable task to develop a HVC with new structure, reveal the hydro-viscous drive mechanism, improve HVC’s control accuracy and dynamic response speed, and establish a control method of jam breakout technology for TBM.The main research contents of this dissertation are as follows:In the first chapter, the background and significance of the research project was elaborated. A new driving scheme of TBM cutter head system was proposed based on contrastive analysis of existing system. Since HVC is the key component of new driving scheme, a review of HVD technology was studied. Then, overseas and domestic research status of fluid flow of friction pair、torque transmission performance and the starting engagement control related to HVC was summarized and also the shortcomings of previous studies was pointed out. Finally the main research contents of this dissertation were put forward.In the second chapter, the advantages of our new driving scheme based on HVC was analyzed, then function and task of the test rig for jam breakout was put forward. According to the special demands of the test rig, a new type of HVC with centrifugal chamber and double piston structure was developed. Then some critical components of HVC was designed, which can provide test condition for studying jam breakout technology for TBMIn the third chapter, the expression of oil film bearing capacity was derived in detail based on the Navier-Stokes equation, which laid a foundation for further theoretical research work. By analyzing the mechanical model of HVC’s frictional plates, the distribution of oil film thickness of HVC was obtained. Then the effects of centrifugal chamber and double piston structure on uniformity of oil film thickness were researched through Fluent simulation. Finally, according to the mechanical and motion model, dynamic balance equation of oil film for HVC with double piston was derived, and its dynamic performance was studied by Adams simulation.In the fourth chapter, the AMESim model for the whole test rig of TBM was established based on the real characteristic of electric motor, load and HVC. Factors such as initial speed and inertia of flywheel、cooling system、oil film thickness control method、structure of HVC on the influence of jam breakout performance of TBM were studied. Consequently, curves of jam breakout torque、rotational speed and shock extent were obtained. In addition, viscous torque curve with twice the load torque and duration of 70 s was achieved to help TBM get out of jam, which can prove that the new driving scheme has the advantages of stronger jam breakout ability and smaller impact to cutter head system.In the fifth chapter, the TBM jam breakout test rig was established. Some experiments such as dynamic and static performances of HVC, characteristic of jam breakout based on hydro-viscous coupling mechanism were carried out, which verified the previous theoretical and simulation results.In the sixth chapter, the conclusion for this paper together with the further study works come to the end.