Excavation load analysis and efficiency optimization of TBM by multi-disc cutter rotary rock-breaking

Efficiency optimization constitutes a pivotal challenge in ensuring both safety and energy efficiency during tunnel construction utilizing Tunnel Boring Machines (TBMs). This paper focuses on the mechanical analysis of excavation loads and the efficiency optimization of multi-disc cutter rotary cutting. A strategic dataset is established through a combination of multi-disc cutter rotary cutting tests and simulation technologies under thrust-torque synergy, enabling a quantitative analysis of the interaction characteristics between multi-disc cutter and rock. The quantitative analysis reveals that as the radius of gyration increases, the interaction range between disc cutter and rock, and the extent and severity of rock damage, exhibit a decreasing trend governed by a power function. Based on this observation, a functional expression for the contact area between the disc cutter and the rock is derived. Building upon this analysis and considering the contact pressure distribution between the disc cutter and rock, a method for calculating excavation loads is established. This method incorporates the rotation of multi-disc cutter and accounts for the varying load distribution across individual cutters. Furthermore, an energy analysis method is integrated to develop an efficiency optimization method aimed at minimizing energy consumption. Compared to this method, the Colorado School of Mines (CSM) efficiency optimization model underestimates the excavation load and specific energy, owing to its inability account for the effects of the disc cutter's rotation on the contact area and rock damage. This study is expected to provide innovative strategies for enhancing energy savings and reducing consumption in TBM excavation.