Theoretical Study of Mechanical Behavior of Tunnels Considering Soil-Machine Interactions

With the rapid development of urban rail transit systems, the shield tunneling technology has become indispensable for urban tunnel construction. However, the theoretical study of the shield tunneling process is not mature enough in view of the complex mechanical properties of the shield machine and the surrounding soil. In this paper, the attitudinal change behavior of earth pressure balanced shield machines (EPB) during the tunneling process is investigated, and comprehensive theoretical expressions for the normal and frictional forces acting on the shield periphery and cutter face are derived. The discretization equations for the normal forces acting on the shield periphery are given based on the meshing and interpolation method. Based on the above studies, the mechanical equilibrium equations of the shield are established to accurately solve for the shield forces and shield attitude characteristics, as well as to verify the computational accuracy of the theoretical solution. Through the analysis of a practical project involving longitudinal tunneling, it is confirmed that the theoretical calculation model can better reflect the mechanical behavior of the earth pressure balanced shield.