Study Of TBM Performance Prediction Model In Multi Stages And Dynamic Design Of Connection Structure

With the development of science, technology and economy, the resources on the land surface are decreasing year by year. Many countries are beginning to develop and use the underground space. The Tunnel Boring Machine (TBM), based on its specialties such as high driving speed, high quality of construction, safer working environment and less pollution to the environment, can work in the long tunnel that deeply under the surface of complex geological features which it is difficult to work by the traditional drilling and blasting methods. So in China and in all over the word, the application of the TBM has a rapid growth in the tunnel’s construction of water conservancy, waterpower, transportation and mining, and has become to be the mainstream of the tunnel construction machinery in the world by now. The disc cutter, as the core of TBM working parts, is the vulnerable parts of TBM because of the directly contact with the rock and suffering more impact loads. So there is very important engineering significance to do the research on the cutter’s theory of broken rock, force prediction model, and improve the cutter and the balance of its force based on the structure of traditional cutter saddle. This topic comes from 973 project (Project number:2013CB035402) and Chinese national natural science foundation (Project number:51375001).The specific work and main thesis of the paper are as follows:1. Aiming at the limitations of prediction model of rock fragmentation, this paper, based on the dense core theory, different rock conditions, considering the disc cutter’s complex force bearing status during the process of rock fragmentation, analyzes the process by disc cutters; considering rock characteristics, types of disc cutters, layout parameters of cutters, tunneling parameters, disc cutter structure parameters, rock fragmentation prediction model of different types of disc cutters group in multistage is deduced, and as the variable of the physical parameters of rock, penetration and cutter space, the linear disc cutter cutting test is carried out, the error on average of vertical force is less than 10%, proves the correctness of the model, provide excitation for the dynamics analysis of cutter saddle.2. Disc cutter-cutter saddle system’s dynamical model is established by concentrated mass method, considering the effect of bold pre-tightening force and damping, established oscillatory differential equation by analyzing relative displacement relationship of each member, and the stiffness of interface and damping coefficient are calculated through empirical formula. The results showes that the stiffness and damping change with the change of bolt preload and wedge vibration displacement. System response is solved by the Newmark method based on the mechanical vibration theory. The vibration of wedge block and disc cutter in each direction is intense, and the values are vertical direction>lateral direction> rolling direction. The study shows that the damping coefficient, the preload and the contact area is the main factor affecting the system dynamic response. Therefore this paper selects the above factors as variables, respectively analyzes the influence of the main mass dynamic response. Results show that when β is 10-3, the vibration is close to the real vibration response; the vertical direction of the force response is positive correlation to the changes of the bolt preload, The change of bolt preload has no effect on the side force, and there is a negative correlation between rolling force and direction of the bolt preload; when the area of joint surface is doubled, the vibration displacement of gauge cutter decreases by 10.60% and 1.63%.3. To verify the correctness of the theoretical model, vibration experiment of cutter saddle is conducted by electro-hydraulic servoforactuator, vibration response is observed under different preload and different load form. When load amplitude increases from 4kN to 4.75kN, the vertical amplitude response of the cutter saddle increases by an average of 0.178kN under 234kN bolt preload, under 300kN bolt preload the vertical amplitude response increases by an average of about 0.35kN, compared with 234kN, it is nearly doubled, which is very close to the input load; While the amplitude of side load responses increase 0.018kN and 0.016kN. There is not a linear relationship between the amplitude and frequency, after 3 Hz, the slope of the amplitude is much greater than the slope before.4. To solve the wedge block of the traditional design is prone to death card, and the problem that vibration of wedge and cutter shaft is strong. This paper designs a new structure of cutter saddle to improve the vibration resistance reducing the damage of cutter saddle, analyzes performance evaluation for new cutter saddle, By comparing the vibration displacement of the disc cutter and wedge block: vertical displacement of disc cutter and wedge block are decreased by 67% and 53%, respectively the rolling direction of the displacement reduces 7.9% and 7.6%, the new structure makes a good vibration absorbing effect, it can reduce the vibration damage of the disc cutter and the bolt greatly.