Structure Design For Main Bearing Of Full Face Rock Tunnel Boring Machine Oriented To Reliability And Vibration Behavior

Since the beginning of21st century, the utilizations of underground space have got greatly attention, and TBM has become the first choose of hard rock tunnel equipment as its advantage in effective, safety, green, and have a broader market outlook. The main bearing, as the key load-carry component, was required high safety, stability, reliability under special work-condition. So, be considered in the traditional design theory and method, the structure design of main bearing based on stability and reliability is very necessary, which is a new direction of the main bearing design. According to the rated load life design, this paper rebuilt the load simulation model to solve lacking load information in early design, and then the stress spectrum was forecasted in complex case, after that, dynamic reliability prediction method of main bearing system was got on basis of structural fatigue reliability calculation model in random stress and the failure-dependence of each parts. Through the analysis of stiffness performance of main bearing system, the vibrational behavior was analyze under the action of time-varying load, combining with the structure parameters and vibrational parameters, a new optimizational design method of parameters was proposed based on the structure fatigue reliability and vibrational behavior.The main work and content can describe as following.Firstly, according to the continuous tunneling characteristics, the simulation method for dynamic tunneling load of cutterhead, considering the complex strata, the layout and load of disc cutter on cutterhead, the computing of complex load for cutterhead, was established. Through the load of cutterhead, load and stress distribution of asymmetric main bearing were computed and stress spectrum under dynamic load was competed, then the distribution parameters of random stress were statistical fitted by the rain flow counting and the treatment of multiple conditions, and that was appropriate to the reliability analysis.Secondly, taking into account the nonlinear degenerate theory and capability dispersion of strength, the fatigue reliability prediction model of main bearing was established based on the traditional stress-strength interference model. With computing the structure reliability through JC methods, reliability of system was forecasted with the failure relationship of parts in system.Thirdly, the formation of main bearing’s vibration and its key parameters was studied for the system dynamics model which is matching the fatigue reliability model and based on the contact model of roller and raceway. Through the research on core dynamics parameters, this paper put forward a equivalent dynamics model and equation based on the contact stiffness and damping of roller and raceway.Finally, with the goal of fatigue reliability and vibrational level and the constraints of system’s design, the optimization model of structure parameters was given in paper. The TBM of one diversion works was analyzed as an example for proving that this method is effective. The comparative analysis on optimizational result shows that the fatigue reliability is improved while vibrational displacements are depressed. So, the optimizational design method is effective and can be used in reliability prediction and structure optimization of main bearing under complex load.