Performance Analysis Of TBM Gripping-Thrusting-Regripping Mechanism Test Bench

The gripping-thrusting-regripping mechanism is the key transmission mechanism of the Full Face Hard Rock Tunnel Boring Machine(TBM)to achieve high efficiency,stability and precision tunneling.Focusing on some problems of the reduced-scale test bench,by taking the surrounding rock simulation mechanism and load simulation mechanism of the test bench as the research objects,this paper implements research on the mechanical structure optimization,static characteristic analysis and finite element simulation analysis to.The main contents are given as follows:(1)After investigating the reasons of the deviation between the contact stiffness of the surrounding rock simulation mechanism and the actual shield-surrounding rock contact in the low stiffness ranges,a method of simulating the contact stiffness of the time-varying surrounding rock is presented by using the combination of disc springs.Moreover,the topological structure of the load simulation mechanism is improved to fulfill the design requirements of load characteristics in operation.By using 3D modeling software,the virtual prototype of surrounding rock simulation mechanism and load simulation mechanism is designed.(2)By considering the variable stiffness characteristics of the disc springs,the mapping relations between the side-shield cylinder parameters and the disc springs stiffness is established.The influence of the crucial parameters of the surrounding rock simulation mechanism on the performance is analyzed to provide a theoretical basis for optimization design of parameters.(3)The relation between the hydraulic cylinders of the load simulation mechanism and the groups of the driving cylinders is established to simulate different load laws in tunneling.The motion and static characteristics of the mechanism are analyzed to design the working pressures and adjusting range of each group of driving cylinder,providing a reference for relevant experimental research.(4)With the aid of ANSYS software,the static characteristics of the improved above-mentioned mechanism are simulated,the stress state of the key parts and the stress distribution of the key parts are derived,providing some references for the performance optimization of the test bench.