TBM Anti-vibration System Design Based On Magnetorheological Principle

Full face rock tunnel boring machine(TBM)is a large-scale complex tunneling equipment integrating machine,electricity,liquid and control.It is widely used in water conservancy,hydropower,highway,railway and municipal engineering construction because of its safety,high quality,high efficiency and environmental protection.As the most important system of TBM,the host system plays the role of turning and advancing the cutter head in the construction process.During normal tunneling of TBM,the cutterhead is likely to cause severe vibration of the main engine system under the action of multi-point strong shock and sudden load,and the extreme vibration often causes serious engineering problems such as cutter head panel cracking,main bearing seal failure and main beam weld cracking,which greatly affects the efficiency and safety of tunnel construction.Therefore,it is very important to analyze the dynamic characteristics and vibration suppression of the TBM host system.At present,the research on TBM vibration mainly focuses on the analysis of dynamic characteristics.The research on TBM vibration reduction is very limited.The only research is mainly to suppress the vibration of TBM girder by designing dynamic vibration absorber.Considering the time-varying displacement characteristics of TBM driving process,dynamic vibration absorber has some deficiencies in stability,and the effect of vibration absorber on TBM vibration control is limited.Taking the open TBM as an example,the vibration characteristics of its main engine system are deeply studied and discussed,and a new intelligent anti-vibration design method is proposed.The main research contents are as follows:1)Based on the theory of multi-rigid body dynamics,the dynamic simulation software Adams is used as the analysis method,and the TBM host system is taken as the research object.The host system dynamics analysis model is established.Then,the constraints of the virtual prototype model are set,and the internal structural parameters of the host system are determined by considering the influences of gear contact parameters,hydraulic cylinder parameters,cutter system parameters and headstock parameters.Using Ls-Dyna to simulate the rock breaking of different types of hobs,the three-direction load spectrum of different hobs is obtained,which provides the input load for the dynamic model.2)Taking the actual TBM parameters of a project as an example,the vibration response of each key component of the host system is obtained through simulation analysis.The correctness of the simulation calculation is verified by the field measured data.The main vibration law of the host system is: the vibration of the cutter head is mainly axial vibration,the maximum acceleration amplitude can reach 2.5g,the longitudinal amplitude is second,and the lateral amplitude is the smallest;During the vibration transmission process,the amplitude of the longitudinal longitudinal vibration acceleration of the headstock is significantly lower than that of the cutterhead,wherein the lateral direction is reduced by 28.14% and the longitudinal direction is reduced by 22.56%.The lateral acceleration amplitude of the front section of the main beam is reduced to 56.67% of the cutterhead,the longitudinal acceleration amplitude is reduced to 55.47% of the cutterhead,and the axial acceleration amplitude is reduced to 55.39% of the cutterhead;The main vibration frequencies of the cutter head,the head frame,the front section of the main beam and other components are concentrated in 0~10Hz,showing obvious forced vibration.3)The sensitivity analysis of the key components of the main engine system is carried out,and the installation scheme and maximum output target of MR damper are determined.According to the maximum output requirement of the damper,a single barrel single rod shear valve magnetorheological damper is designed.The magnetic circuit parameters of the damper are designed in detail combined with Ampere loop theorem and Gauss theorem.The rationality of the magnetic circuit design is verified by the finite element analysis of ANSYS electromagnetic field.4)The dynamics simulation analysis of the TBM host system under different conditions was carried out with different types of working conditions,different cutter heads and different cutterhead speeds.And the influence of MR damper on the vibration of main engine system under different factors is discussed.The results show that the MR dampers have a certain effect on the vibration suppression of the main engine system under different factors.Under the action of the dampers,the axial acceleration amplitude of the cutter head and the front section of the main beam decreases by 6%~49%,and the root mean square value decreases by 35%~54%.This confirms the effectiveness of the anti-vibration scheme design and achieves the expected goal.