摘要:
受近邻工程突发扰动影响，饱水软土盾构隧道频现局部非稳定渗流，诱发接头压溃、管片开裂等不可逆的结构性非连续裂损，严重损害隧道结构的力学和耐久性能，威胁其运营安全和寿命。如何表征连续-非连续介质渗流的水力特性，以及如何描述流体、固体、非连续裂损耦合问题，成为精准预测隧道结构裂损风险及精准评价隧道结构韧性的关键。为此，基于相场理论，构建了统一断裂相场理论框架，提出了流-固-相多场耦合数值方法，精准追踪隧道结构裂损特征的演化，进而建立了基于裂损特征演化的隧道结构韧性评价模型。结合上海地铁18号线盾构隧道裂损实例开展研究，结果表明：局部非稳定渗流导致了隧道结构的力学失衡，诱发了接头压溃和管片开裂等局部裂损现象；随着裂损风险的演化，裂损截面处的内力出现了显著的重分布，这一过程伴随着能量的释放，使得隧道结构的韧性明显下降。研究为饱水软土盾构隧道裂损演化分析提供了可靠理论方法，为隧道结构的韧性评价和恢复提供科学依据。
Abstract:
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.
下载:
