钢筋锈蚀作用下盾构隧道结构损伤劣化性能

在长期的水土荷载和侵蚀性物质联合作用下，盾构隧道钢筋混凝土衬砌结构会经历腐蚀-损伤-劣化过程而逐渐失效，导致服役性能大幅降低。本文引入内聚力模型（CZM）及混凝土塑性损伤模型（CDP），建立考虑钢筋混凝土间粘结滑移的盾构隧道衬砌锈蚀三维数值模型。综合考虑钢筋锈蚀引起的自身力学劣化、混凝土有效截面损失及钢筋混凝土粘结性能退化等因素，分析了围岩水土荷载和钢筋锈蚀耦合作用下衬砌结构形变、损伤演变规律和整体结构劣化特征。研究表明：1）锈蚀作用导致衬砌结构刚度降低，大大加深了衬砌结构的变形程度。锈蚀造成衬砌结构不同部位的刚度损失不同，反映了锈蚀作用下衬砌结构损伤的差异性。2）衬砌结构的围岩侧与临空侧损伤差异较大。相同锈蚀率下，衬砌受压侧受到挤压作用，限制裂缝的发展，导致受压侧损伤很小。3）在锈蚀过程中隧道衬砌结构拱顶弯矩不断减小，拱顶损伤不断加深，损伤区域逐渐扩展，截面刚度损伤最显著。4）衬砌结构自身性能不断劣化，出现内力重分布。衬砌结构的裂缝多出现在围岩侧。研究成果可为隧道衬砌结构服役性能的评估提供参考。

Study on Damage and Deterioration of Shield Tunnel Structure under Reinforcement Corrosion

Under the combined action of long-term soil and water loads and aggressive materials, the reinforced concrete lining structure of shield tunnels will undergo a reinforcement corrosion-concrete damage-deterioration performance process and gradually fail, resulting in a significant reduction in service performance. In this paper, the cohesive zone model (CZM) and the concrete damaged plasticity model (CDP) are introduced to establish a three-dimensional numerical model of shield tunnel lining corrosion considering the bond slip between reinforced concrete. The lining structure deformation, damage evolution law, and overall structural deterioration characteristics under the coupling effect of the surrounding rock, soil, and water load and reinforcement corrosion are analyzed, taking into account the factors such as mechanical deterioration caused by reinforcement corrosion, loss of effective concrete section and degradation of reinforced concrete bonding performance. The research results were concluded as follows. (1) Reinforcement corrosion leads to a reduction in the stiffness of the lining structure and greatly deepens the degree of the lining structure deformation. The corrosion causes different stiffness losses in different parts of the lining structure, reflecting the variability of lining structure damage under the action of corrosion. (2) The lining structure has a large difference between the damage on the perimeter rock side and the adjacent air side. With the same corrosion rate, the pressurized side of the lining is subject to extrusion, which limits the development of cracks and leads to little damage on the pressurized side. (3) In the corrosion process, the tunnel lining structure vault moment decreases, the vault damage deepens and the damaged area gradually expands. The cross-sectional stiffness damage is the most significant. (4) The performance of the lining structure is deteriorating continuously, and internal force redistribution occurs. The cracks of the lining structure are mostly found on the surrounding rock side. The research results can provide a reference for the evaluation of the service performance of the tunnel lining structure.