Research On Contact Stress Distribution Uniformity Between Surrounding Rock And Boot Of Tunnel Boring Machine

Full face rock tunnel boring machine(TBM) is widely used in highway and railway tunnels, urban subway, water conveyance tunnel, the national defense project, because there are many advantages such as the excavation speed, good engineering quality and construction safety.The boot compress the surrounding rock, to balance the forces of support and propulsion by friction on the contact surfaces between the boot and surrounding rock in the process of TBM moving. There are many problems during the construction process, such as the stress is uneven in the surface of cutter head, the support the performance is not stable, the surrounding rock stress inequality and so on, because of the heavy load, the interrupt dynamical load and intense impact load which come from outside environment. In order to study the uniformity of stress distribution, several research works have carried outThe equilibrium equation of the boot is established based on the force in the TBM. According to the model of the secondary stress state of surrounding rock, obtained the boundary condition of surrounding rocks, constructed an contact simulation model of the boot’s middle part first contact with the surrounding rock and the boot’s two ends part first contact with the surrounding rock. Meanwhile, constructed an contact simulation model of surrounding rock under uniformly load. Then solved two models by using the finite element software,The simulation results were processed by using MATLAB. Obtained the stress and displacement graphs of three kinds of contact models. As well as the relationship between the stress and the normal load, and the relationship between the displacement and the normal load.The concept of uniformity of stress distribution was proposed, the indicator of uniformity of stress distribution λ was set-up. Analyzed the uniformity of stresses distribution in the contact surface of surrounding rock and boot by using the indicator of uniformity of stress distribution λ. The research study provides the theoretic foundation for reinforcing the surrounding rock when through the areas of geological complex and how to operate TBM.The contact simulation models between boot and surrounding rock was established with several different radius of boot and surrounding rock. The influence of the different radius on the uniformity distribution of stresses was analyzed. The results will provide theory basis for optimizing the the construction of boot and improving the uniformity of stress distribution in the contact surfaces.