Simplified Calculated Method for Pipeline Deformation Induced by Shield Tunneling

Tunnel excavation can easily cause settlement and deformation of the surface of the overlying surface，which will further cause the stress and deformation response of the existing pipeline. Based on this，a simplified method for calculating the deformation of the overlying pipeline due to shield excavation is proposed. Firstly，the Loganathan formula is selected to solve the additional stress along the pipeline induced by tunneling underlying，and the pipeline is further simplified into an infinitely long beam resting on the Pasternak foundation. The influence of the lateral displacement of the infinite distal soil on the existing pipeline is introduced. Then，the mechanical equilibrium method is used to obtain the control equation of the vertical force and deformation of the pipeline. The finite difference method is selected to obtain the numerical analytical solution of the pipeline deformation and internal force analysis. The case analysis shows that，compared with the degradation analysis of this method，the calculation results are closer to the measured data of an actual project in the existing literature，which verifies the reliability of this method. Further parameter studies show that increasing the vertical clearance between the tunnel and the pipeline causes a nonlinear reduction in the stress and deformation of the pipeline. Increasing the volume loss rate results in a linear increase in the deformation and inner force of the pipeline. Increasing the pipeline bending stiffness reduces the pipeline deformation but greatly increases the pipeline bending moment. © 2024 Hunan University. All rights reserved.