Mechanical characterization of the load distribution on the cutterhead–ground interface of shield tunneling machines

• A mechanical decoupling analysis for cutterhead–ground interaction is presented.
• A bilinear description model for the load distribution is established.
• Model effectiveness is verified by experimental and numerical simulation results.
• Approximate calculation equations for thrust and torque on cutterhead are given.
• The work provides a theoretical reference for load analysis and cutterhead design.

The paper proposes a mechanical characterization and approximate calculation method to determine the load acting on the cutterhead–ground interface of an Earth Pressure Balance (EPB) shield tunneling machine. Through a mechanical decoupling analysis of the coupling interaction between the cutterhead and the ground, the basic expressions for the normal and tangential stresses acting on the tunneling interface between the cutterhead and the ground are developed. For ease of use in engineering applications, the stress expressions are modified and simplified with the consideration of several engineering factors, such as the stress limit that the ground can bear, the overburden, and the topological structure of the cutterhead. A “bilinear” description model for the load distribution is then established; the effectiveness of this model is discussed and verified by a comparison with the laboratory experimental results and the numerical simulations in existing research. The equations for the approximate calculation of the thrust and torque on the cutterhead are also presented. This work may improve the simplified hypothesis that the cutterhead load is uniformly or linearly distributed in the current equipment design and load calculation, thereby providing a theoretical reference for cutterhead design and layout and for the analysis and calculation of loads in the tunneling process.