Research On Modeling And Dynamic Behavior Of Tunnel Boring Machines With Variable Constraints

Tunnel Boring Machines assemble mechanical,electrical and hydraulic technology. They are becoming the most common tools in tunneling gradually because they advance fast with high qualities and have little influence on environments. Considering the complexity of structures of TBM and variable geological conditions, it is of great importance to study the dynamic behavior of TBM with variable constraints in mixed geological conditions.The dynamic model of the thrusting system is made and the transmission of forces in the system is analyzed. Then the coupling of loads on the cutterhead and the stiffness of the surface between the gripper shoes and rocks is studied and the dynamic behavior of thrusting system is explored. Finally assessment targets of dynamic behavior in mixed geological conditons are provided. The main contents are listed as follows:(1)Structures of each part in the thrusting system and their relationships are analyzed and then the working principle is studied. The dynamic equation is deduced in Lagrange Method with lumped parameters.(2) Stress model of hobbing cutter is made according to rock extrusion theory,then force and torsion on the cutterhead in mixed stratums are deduced. The coupling of loads on the cutterhead and the stiffness of the surface between the gripper shoes and rocks is established combining stiffness properties of the surface between the gripper shoes and rocks and loads properties of the cutterhead. The coupling in single geological layer, several geological layers and interfaces at different angles is researc hed.(3)Thrusting ways of TBM are concluded as two typical ways: straight thrusting and curved thrusting. Dynamic behaviors in the two typical ways are studied when gripper surfaces are of different hardness.(4)Interval numbers are induced to describe uncertainties of proportions of hard and soft rocks in the mixed geological conditions and angles of interfaces. Dynamic behaviors of TBM thrusting system are researched when rocks change with the variation of geological conditions in two typical thrusting ways. Assessing targets of thrusting behavior are set up to assess the property of thrusting system in typical geological conditions and the assessing results are verified in working practice.