Indoor tests on the mechanical response of tunnel lining under the influence of pipeline leakage

Pipeline leakage is a common issue encountered in urban areas, significantly contributing to the deterioration of tunnel structures and even posing a risk of ground collapse. This study investigates the mechanical response of tunnel structures influenced by adjacent pipeline leakages through indoor tests. A scaled tunnel model with a simulated lining system was constructed, and pipeline leakage scenarios were replicated by introducing controlled water pressures at the predefined location. The deformation and stress redistribution in the lining under varying leakage locations and durations were monitored. Experimental results reveal that the location of the pipeline leakage concerning the tunnel had a great impact on the distribution of the leakage zone. The presence of the tunnel affected the expansion of seepage water from the pipeline in the strata. The pipe leakage above the tunnel resulted in a maximum surface settlement of 2.66 mm, whereas the horizontal movement of the pipe leakage location reduced the surface settlement by 10-15 %. Change in location of pipeline leakage induced uneven deformation of the strata, and the settlement progression behavior exhibited an initial gradual development stage (0-2 h), accelerated subsidence stage (2-10 h), and stabilization stage (10-14 h). Uniform settlement of the strata due to pipeline leakage led to a dynamic mechanical response of the lining structure, and the internal forces of the lining structure also manifested obvious asymmetric features. Lining leakage resulted in a 41.9 % and 22.1 % increase in bending moment and axial force of the lining structure, respectively. The lining structure bias caused by pipeline leakage will deteriorate the mechanical behavior of the tunnel structure. The findings of this paper can provide a reference for the prevention and control of leakage of adjacent pipelines in subway tunnels.