Investigation of construction settlement for super-long bidirectional circular pipe jacking - launching shaft structure

This study addresses construction disturbances caused by dense surface traffic and complex water-rich strata in urban underground construction. Based on the full-scale Taicang Port central heating pipeline project, it investigates large-diameter bidirectional circular pipe jacking and launching shaft excavation. A three-dimensional finite element model was developed in ABAQUS and validated against field monitoring data. The effects of three key parameters—pipe diameter-to-shaft diameter ratio, vertical alignment deviation, and jacking force coefficient—on the deformation and stability of the shaft–soil system were examined. A load-ratio-modified hyperbolic settlement prediction model was proposed, in which the model coefficients were calibrated and updated using construction-stage monitoring data to support settlement prediction and early warning. The combined effects of multiple parameters on the underground structures were analyzed, and a design-construction-monitoring control framework was applied in the project. The results provide a practical reference for similar urban underground projects in water-rich strata. The main contributions are the validated full-process simulation of a super-long bidirectional circular pipe jacking launching shaft, the identification of key parameters affecting shaft–soil deformation, and a monitoring-calibrated settlement prediction method for similar projects.