Abstract: In utility tunnel construction, the accuracy of thrust predictions for U-shield pipe-erecting machines is low and the thrust cannot be effectively controlled. To address these challenges, a case study is conducted on a utility tunnel project in the Xiong’an New Area, and a thrust calculation method based on Coulomb theory and the Mckyes-Ali blade cutting model is established. This method incorporates slope gradient, plate cutting angle, and shield-soil interface friction angle. Next, the ABAQUS finite element software is utilized to numerically simulate the dynamic jacking of U-shield pipe-erecting machines. The simulated thrust is then compared with measured data to validate the model’s feasibility. The findings are as follows: (1) Side-seam backfilling leads to sidewall deformation, which increases side friction resistance from 1 453 kN to 1 985 kN, resulting in greater thrust as jacking progresses. (2) A comparison of the simulated data for the slope slip surface and component resistance with the theoretical model reveals that side earth pressure is the main source of prediction error. (3) A dimensionless sensitivity function is introduced to analyze the effects of various factors on thrust. The analysis shows that a slope gradient range of 45°－38° behind the shield is reasonable for tunnel construction. Moreover, the reasonable ranges for the plate cutting angle and reserved soil thickness are 30°－50° and 0.4－2.0 m, respectively. Detachable plates should be designed to control the thrust of U-shield pipe-erecting machines.

Key words: U-shield pipe-erecting machine, thrust, theoretical model, numerical simulation, influence parameter, sensitivity analysis