Numerical Computing Research on Tunnel Structure Cracking Risk under the Influence of Multiple Factors in Urban Deep Aquifer Zones

During the operation period of tunnels in urban deep aquifer zones, the geological environment around the tunnel is complex and the surrounding strata are rich in groundwater, which often poses a risk of structure cracking and groundwater leakage, seriously threatening the tunnel’s safety. To reduce the risk of tunnel cracking, a theoretical calculation model and a three-dimensional concrete–soil interaction thermo-mechanical coupling numerical computing model was established to analyze the tunnel structure cracking risk under the influence of multiple factors in urban deep aquifer zones. The response mechanism of structural stress and deformation under the influence of the grade of rock and soil mass, overburden thickness, temperature difference, structure’s length–height ratio, structure’s thickness, and structure’s elastic modulus was investigated, and the stress and deformation response characteristics of the structure with deformation joints were explored. The results show that the maximum longitudinal tensile stress of the structure increases with the increase in the grade of rock and soil mass, overburden thickness, temperature difference, structure’s length–height ratio, and elastic modulus. The temperature difference has the most significant impact on the longitudinal tensile stress of the structure, with the maximum tensile stress of the structure increasing by 2.8 times. The tunnel deformation joints can effectively reduce the longitudinal tensile stress of the structure, and the reduction magnitude of the tensile stress is the largest at the deformation joints, which is 64.7%.