软土地区已建盾构隧道病害机理及治理对策研究

With the rapid development of urban rail transit construction, a large number of shield tunnels have been built in the deep soft soil area of the southeast coast of China. However, the engineering cases of the diseased existing tunnels in soft soil increased in recent years. The uneven settlement and large lateral convergence of tunnel cause severe damages to the tunnel structure and the failure of waterproof, which threats the safe operation of the tunnel. "Micro disturbance grouting" method is proved to be effective in controlling large tunnel deformation, but the design scheme and selection of grouting parameters mainly depend on the measured data and engineering experience instead of systematic theoretical and experimental studies. In this project, laboratory grouting tests, model tests, in-situ measurement, analytical calculation and numerical simulation will be used to investigate the disease mechanism and processing measure of existing tunnels in soft soil. The deformation characteristics of tunnel at the disease stage will be analyzed. The diffusion law of grout and its influence on surrounding soft soil will be studied. Moreover, the additional stress caused by grouting process and its influence on the tunnel lining will be clarified. Finally, the long-term effect of tunnel deformation control by grouting will be analyzed. This project will establish the evaluation system of the grouting method to control the tunnel deformation, which provides a theoretical basis for the project design, parameter selection and effect evaluation of the "micro disturbance grouting" method.

随着城市轨道交通建设的飞速发展，在我国东南沿海的深厚软土地区修建了大量盾构隧道。而软土中已建盾构隧道发生病害的工程案例也逐年增多，其中纵向的不均匀沉降和横向过大的收敛变形会引起隧道结构的破坏与防水的失效，影响隧道的安全运营。“微扰动注浆”法是整治隧道产生大变形的一种有效手段，但整治方案的设计与注浆参数的选择主要依赖于实测数据和工程经验，缺乏系统的理论和试验研究。本项目拟通过室内注浆试验、模型试验、工程实测、理论研究和数值分析开展针对软土地区已建盾构隧道的病害机理及治理对策的系统研究，分析隧道在病害阶段的宏观变形特点，研究浆液在软土中的扩散规律和对土体的影响，揭示注浆在隧道衬砌上产生的附加应力分布规律，探究病害治理阶段的附加应力对衬砌结构的影响，分析注浆治理隧道的长期效果，建立注浆法治理隧道病害的评价体系，为工程中采用“微扰动注浆”法治理隧道病害的方案设计、参数选取和效果评价提供理论依据。

随着城市轨道交通建设的飞速发展，在我国东南沿海的深厚软土地区修建了大量盾构隧道。而软土中已建盾构隧道发生病害的工程案例也逐年增多，其中纵向的不均匀沉降和横向过大的收敛变形会引起隧道结构的破坏与防水的失效，影响隧道的安全运营。“微扰动注浆”法是整治隧道产生大变形的一种有效手段，但整治方案的设计与注浆参数的选择主要依赖于实测数据和工程经验，缺乏系统的理论和试验研究。本项目拟通过室内注浆试验、模型试验、工程实测、理论研究和数值分析开展针对软土地区已建盾构隧道的病害机理及治理对策的系统研究，分析隧道在病害阶段的宏观变形特点，研究浆液在软土中的扩散规律和对土体的影响，揭示注浆在隧道衬砌上产生的附加应力分布规律，探究病害治理阶段的附加应力对衬砌结构的影响，分析注浆治理隧道的长期效果，建立注浆法治理隧道病害的评价体系，为工程中采用“微扰动注浆”法治理隧道病害的方案设计、参数选取和效果评价提供理论依据。