为了研究粉土层越江盾构隧道结构受力演化过程以及提出对应的隧道结构安全评价方法，依托苏通GIL综合管廊工程，以水陆交界粉土地质区段错缝拼装盾构结构为对象，采用梁单元嵌入方式，建立考虑斜螺栓连接构造的三维仿真计算模型，分析泥砂淤积和淤滩作用下管片结构应力分布与变形裂损发展过程，揭示外力影响下结构力学损伤演化规律；进而结合设计、规范要求及类似工程实例，提炼粉土层隧道结构长期安全变形控制指标，制定基于最不利原则的安全评价分级标准。研究表明： 1）在淤积和淤滩作用下，结构损伤次序均为混凝土达单轴抗压强度、混凝土达三轴抗压强度和钢筋屈服； 2）淤积工况的竖向收敛依次为606、81、1138 mm，淤滩工况的竖向收敛依次为861、1172、1479 mm，淤滩导致的竖向收敛13~15倍于淤积工况收敛，计算数据基本符合工程经验； 3）取便于监测的钢筋应力、螺栓轴力和接缝张开作为长期健康监测变形控制指标，根据结构损伤状态和设计要求，制定4级评价标准。

It is very important to study the evolutionary process of structural of rivercrossing shield tunnel in silt stratum and the structural safety evaluation method. Hence, by using beam element embedded mode, a 3D numerical simulation and calculation model for shield structure of land and water connection section of Sutong GIL Utility Tunnel in silt stratum is established considering oblique bolt connection structure; the stress distribution law and development process of deformation damage of segment structure under the actions of deposition and beaching are analyzed; the evolutionary process of structural mechanical damage under the action of external force is revealed; and the deformation control standards and the safety evaluation standards based on the most unfavorable condition of the tunnel structure in silt stratum are proposed by case study. The study results show that: (1) The sequence of structural damage under the actions of deposition and beaching is the uniaxial compressive strength of concrete, triaxial compressive strength of concrete and the yield of steel; and the tunnel vertical convergences are 60.6 mm, 81 mm and 113.8 mm and 86.1 mm, 117.2 mm and 147.9 mm under the actions of deposition and beaching, respectively. (2) The tunnel vertical convergence induced by the action of beaching is 1.3-1.5 times that induced by the action of deposition; and the calculated results coincide with the actual data. (3) The easilycollected deformation monitoring indices, i.e. rebar stress, bolt axial force and joint open, should be selected; and a 4level safety evaluation standard should be determined according to the structural mechanical damage and the requirements of design.