Study of the influence of deviations in both jacking force and cutterhead torque during shield tunnelling in soft ground

During shield tunnelling, vertical ground displacement is significantly influenced by deviations in both jacking force and cutterhead torque. This study investigates the effects of deviations in these parameters on ground displacement via numerical simulations. On the basis of measured data from the Zhubai-Longgang Sewage Connecting Pipeline Project in Shanghai, a parametric analysis was conducted with ABAQUS software to simulate the effects of deviations in jacking force and cutterhead torque on vertical ground displacement. The results indicate that a positive deviation in jacking force increases the arch ratio (R) ahead of the shield cutterhead, leading to greater ground heave. Additionally, the positive area of the arch ratio contracts towards the tunnel's central axis with increasing cutterhead torque deviation, further increasing ground heave. The study also revealed that cutterhead torque deviation has a more pronounced effect on ground heave than does jacking force deviation. The maximum ground heave converges when the cutterhead torque deviation extends over an 8-ring distance, while this result occurs when jacking force deviation extends over a 1-ring distance. When the deviations in both jacking force and cutterhead torque are combined, the maximum ground heave is the linear superposition of the independent effects of each parameter. The relationship between the combined deviation distance and the maximum ground heave can be expressed with a power function.