To reveal the mechanical response mechanism of bolted connections during the jacking construction of prefabricated utility tunnels, this study combines field monitoring and numerical simulation based on the utility tunnel project in Xiong’an New Area. The evolution characteristics and spatial distribution patterns of bolt stress are systematically investigated. The results indicate that during the jacking and unloading stages, bolt connection stress exhibits a V-shaped spatial distribution with opposite evolutionary trends. This reflects both the weakening effect of transient construction loads on the connection system and the self-recovery characteristics after unloading. Segments at the launching stage experience the most complex loading conditions, with bolt stress displaying a nonlinear W-shaped gradient distribution. The mechanical mechanism transitions from being jacking-load dominated to stratum-load dominated as construction progresses. The distribution of bolt stress shows pronounced non-uniformity, with higher values at the upper edge and lower values at the lower edge. Compared to the lower edge, bolt stress at the upper edge of segments 1–5 attenuates by an average of 25.52–37.63%. This non-uniformity results from the coupled effects of ground friction, which dissipates jacking stress at the bottom while inducing forward tilting of the upper structure, thereby causing greater compression and rebound of the waterproof rubber strip at the upper edge. The non-uniformity coefficient decreases linearly with construction progress, reflecting a transition from an unstable to a uniformly stressed state. The cumulative effect of jacking load exhibits stagewise attenuation along the utility tunnel. In segments 1–2, significant strain concentration occurs, with peak compressive and tensile strains. In segments 3–4, direct jacking influence weakens, but delayed strain deterioration is observed, with maximum compressive strain reaching only 69.72% of that in the initial stage. By segment 5, the jacking effect attenuates to background levels. The relationship between bolt stress and jacking spacing follows an exponential decay function. Bolt stress during the loading stage is approximately 76.99–89.07% of that during the unloading stage. Deformation at the roof is significantly greater than that at the floor and sidewalls, consistent with bolt stress distribution patterns.
Sui et al. (Mon,) studied this question.