Abstract: Jacking prestressed concrete cylindrical pipe (JPCCP) is widely used in large-section water diversion projects. The pipe-surrounding soil and water pressures and the structural responses during construction are critical to ensuring project safety; however, in-situ measurements remain limited. Based on an ultra-large-diameter JPCCP project in China, full-scale field monitoring was conducted in the whole jacking process. Results indicate that the contact pressure around the pipe was essentially synchronized with the slurry pressure and could be classified into high-pressure and low-pressure phases corresponding to the grouting procedure. The effective earth pressure theory proved reliable in evaluating the pipe–soil–slurry contact states, with measurements indicating that the pipe remained in a persistent floating state. Axial deformation of the pipe exhibited periodic fluctuations induced by the intermittent jack–stoppage cycle, and the hoop deformation was characterized by an asymmetric distribution—vertical compression and lateral tension. The intermediate and exterior-reinforced concrete layers maintain coordinated deformation responses, even under complex loading conditions. Compared to traditional pipe, JPCCP structures must accommodate a complex interplay of jacking force transmission, non-uniform contact pressure, and interface shear coordination, which reflects the three-dimensional force mechanism of 'pipe-soil-slurry-structure' quaternary coupling.