Mechanistic analysis of TBM cutterhead-ground interaction under mud build-up effect

Introduction In tunnel construction using TBMs, the complex mineral composition of strata and hydrogeological conditions often induce cutterhead mud build-up, which results in sharp increases in torque and thrust, thereby reducing excavation efficiency. Understanding the interaction between the TBM cutterhead and the surrounding ground under cutterhead blockage conditions is therefore a critical challenge for improving tunnelling efficiency. Methods This study develops a cutterhead load model that explicitly incorporates both aperture ratio and mud coating effects, and establishes a load-prediction framework for TBM excavation in composite strata. Results The validity of the proposed model is verified using field monitoring data. On this basis, the influence of aperture ratio on excavation loads is systematically analysed. Discussion An optimization strategy—maintaining a relatively large aperture ratio—is proposed to enhance TBM tunnelling efficiency, providing effective theoretical support and practical guidance for addressing cutterhead mud build-up.