According to construction condition and degradation environment of Shanghai Yangze River Tunnel, which is a long-distance underwater shield tunnel with the largest diameter in world at present, the effective thickness of lining is chosen as a parameter for lining degradation calculation based on lining degradation mechanism and tunnel engineering codes. A lining degradation model of underwater shield tunnel, considering soil properties and overlaying soil thickness, is established in accordance with the strength reduction method to effective thickness of lining. Analyzing different situation of lining degradation by numerical simulation method, expressive characteristics and development rules of the tunnel deformation are researched and discussed. According to the results, it is demonstrated that the above mentioned analysis method can be adopted to evaluate the deformation state of underwater shield tunnel during lining degradation, and the calculation results are reliable and reasonable. As a new lining degradation analyzing method, it will provide theory foundation and technology support for tunnel health diagnosing, and also provide valuable reference and scientific instruction to timely maintain and appropriately service for operation and management department.%针对目前世界最大直径水下盾构隧道的工程背景和劣化环境,通过分析衬砌劣化机理和行业规范标准确定了以有效厚度考量衬砌结构劣化,采用强度折减原理对强度参数进行逐步地折减,建立了考虑地层土性和覆土厚度影响的水下盾构隧道衬砌劣化模型,运用数值计算方法分析了衬砌劣化的多种组合工况,从而对衬砌劣化引起上海长江隧道(崇明越江通道)变形的特征表现和趋势规律进行了研究和探讨.研究结果表明:基于有效厚度折减的衬砌劣化分析方法能够有效地反映劣化后隧道结构的整体变形状况,且计算结果可靠合理,可为盾构隧道健康状态诊断与分析提供理论依据和技术支持,也可为运营管理部门正确及时的养护维修提供借鉴和指导.
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