Unified phase-field numerical simulation and resilience evaluation on crack damage evolution of shield tunnels in saturated soft soil[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20241244
Citation:
Unified phase-field numerical simulation and resilience evaluation on crack damage evolution of shield tunnels in saturated soft soil[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20241244
Unified phase-field numerical simulation and resilience evaluation on crack damage evolution of shield tunnels in saturated soft soil[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20241244
Citation:
Unified phase-field numerical simulation and resilience evaluation on crack damage evolution of shield tunnels in saturated soft soil[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20241244
Due to sudden disturbances caused by nearby construction projects, shield tunnels in saturated soft soil frequently experience localized unstable seepage. This may induce irreversible structural discontinuities, such as joint crushing and segment cracking, severely compromising the mechanical and durability performance of the tunnel structure, ultimately threatening its operational safety and service life. Characterizing the hydraulic properties of continuous-discontinuous media and describing the coupling problems among fluid, solid, and discontinuities have become crucial for accurately predicting the crack damage risk in tunnel structures and evaluating their resilience during crack damage evolution. To address these problems, a unified fracture phase-field theory framework was constructed based on phase-field theory, and an innovative numerical method for fluid-solid-phase multi-field coupling was proposed. This method can precisely capture the evolution of crack damage characteristics in tunnel structure. Consequently, a resilience evaluation model based on the crack damage evolution was established for tunnel structures. Studies on the crack damage accidents of the shield tunnel, Shanghai Metro Line 18, show that localized unstable seepage leads to mechanical imbalances of the tunnel structure, which in turn induces local damage phenomena such as joint crushing and segment cracking. As the crack damage risk evolves, there is a significant redistribution of internal forces at the crack damage cross-sections, accompanied by energy release, which significantly reduces the resilience of the tunnel structure. The related research findings provide a reliable theoretical method for analyzing the crack damage evolution of shield tunnels in pressurized water-rich soft soil, and offer scientific basis for the resilience evaluation and restoration of tunnel structures.