为保障高水压强渗透地层中大直径盾构对接贯通施工的地层与结构稳定，以江阴靖江长江隧道工程为背景，采用数值分析、模型试验与现场验证相结合的方法，对贯通施工中的关键技术问题开展系统研究： 针对对接段既有结构拆除与新建结构施作，提出 “分层拆除卸载、同步施作加载” 的变形控制方法，施工过程中的结构最大位移为7.7 mm； 通过分析冷冻管局部及整体失效对冻结地层温度的影响，明确了停冻48 h极端工况下冻结体的稳定特性；开展手动、半自动、水刀3种钢板切割方式的对比试验，确定效率高且兼具灵活性的手动切割为现场拆除施工的主要方式； 完成-30 ℃低温环境下的钢板焊接试验，经力学性能检测，焊接质量均满足设计要求； 建立热扰动评估体系，有效验证了冻结壁的施工安全性； 开展钢壳混凝土填充工艺试验，验证了保障混凝土填筑密实性的实用方法； 提出狭小空间环境下主驱动“三步拆除法”并开展工艺试验验证，该方法现场实施后，先行与后行盾构的最大沉降值分别仅为5.3 mm 和7.7 mm，成功实现2台300 t主驱动的连续、高效拆除。
In this study, a case study is conducted on the Jiangyin-Jingjiang Yangtze River Tunnel Project and numerical analyses, model tests, and field verifications are employed to systematically analyze the key technical issues associated with breakthrough construction of a large-diameter shield docking section in high-water-pressure and permeable strata, thus ensuring the stability of strata and structures. A deformation control method involving “layered dismantling and unloading with synchronous construction and loading” is proposed for dismantling the existing structures and constructing the new structures within the docking section, resulting in a maximum structural displacement of 7.7 mm. The influence of local and overall failure of freezing pipes on the temperature of frozen strata is analyzed, clarifying the stability characteristics of the frozen body under the extreme working condition of 48-h freezing suspension. Comparative tests of three steel plate cutting methods—manual cutting, semiautomatic cutting, and water jet cutting—are conducted, determining the manual cutting featuring high efficiency and good operational flexibility as the main method for onsite structural dismantling. Steel plate welding tests are performed under a low-temperature environment of －30 ℃, and the welding quality is verified to satisfy the design requirements through mechanical performance tests. In addition, a thermal disturbance evaluation system is established to effectively verify the construction safety of the frozen wall. Process tests on the filling technology of steel shell concrete are carried out to verify the practical method for ensuring the filling compactness of concrete. A three-step dismantling method for the main shield drive in narrow space is proposed and verified through process tests. After onsite implementation of this method, the maximum settlements of the leading and following shield machines are 5.3 mm and 7.7 mm, respectively, realizing the continuous and efficient dismantling of two 300 t main drives.
