Abstract: Removal of shield segments disrupts compressive equilibrium between tunnel rings, triggering thrust loss that induces structural deformation and ring joint leakage. This poses a critical challenge for fortification section of Xi'an Metro, constructed through ground fissures using the "shield before expansion" method. To investigate thrust loss and ring joint openings induced by segment removal, a 1∶10 scale model test is conducted using a custom-designed loading platform. The efficacy of multiple reinforcement measures-including bolt re-tightening, variable tensioning ranges/stiffness, and combined strategies-is evaluated. Experimental data inform a revision of the conventional whole-pipe longitudinal stress transfer model. Results show that: thrust loss intensifies proximal to the removal zone, with residual thrust stress following an exponential distribution. Segment removal induces ring joint openings up to 4.1 mm, and significantly degrades waterproofing integrity on both sides of the fortification section. Bolt re-tightening improves residual thrust stress uniformity but minimally mitigates joint openings. Channel steel tightening measures are effective in increasing residual thrust stress, enhancing stress uniformity, and reducing ring joint opening. However, these improvements do not increase proportionally with the tensioning range or stiffness. Using a combined measure of "14b channel steel tightening 10 rings + bolt re-tightening" achieves the same effect as either "14b channel steel tightening 15 rings" or "16b channel steel tightening 10 rings." An optimized longitudinal stress transfer model, incorporating ring joint effects via series-stiffness principles, is derived to quantify thrust loss influence ranges. This model aligns more closely with test data and field observations, indicating a longitudinal influence range 1/10 of the whole-pipe model's estimate. Fundamentally, ring joint effects amplify the longitudinal segment-ground displacement gradient, elevate stress transfer gradients and finally alter thrust transmission paths and influence extents.