南京和燕路过江通道盾构穿越长江大堤的沉降分析及控制研究

Research on settlement analysis and control measures:a case study of the Nanjing Heyan road river-crossing shield tunnel passing under the Yangtze River embankment

南京和燕路过江通道采用超大直径泥水盾构(开挖直径15.07 m)施工,需穿越南京八卦洲防洪大堤。以此工程为背景,借助有限元软件对超大直径盾构穿越长江大堤建立三维数值模型,在考虑土体开挖,泥水支护,管片衬砌,壁后注浆以及地层损失等施工要素的基础上,对施工过程进行精细化模拟。将数值解与监测数据对比,验证了模型的合理性,进而研究泥水盾构过堤时大堤沉降的动态变化规律,并分析不同注浆压力对大堤沉降的影响。最后从泥水压力控制、同步注浆量实时检测等7个方面总结本工程泥水盾构过堤时的沉降控制技术措施。大堤实测最大沉降量为21.7 mm,控制在了堤身高度的0.5%以内,取得了很好的控制效果,可为类似工程提供参考。

Nanjing Heyan Road cross-river tunnel is constructed with a super-large-diameter slurry shield(excavation diameter 15.07 m),which needs to pass through the Nanjing Baguazhou embankment.With this project as the background,the finite element analysis software is employed to establish a three-dimensional numerical model of the super-large shield tunnel crossing the Yangtze River embankment.Taking into account construction factors such as soil excavation,slurry support,segment lining,grouting behind the lining,and ground loss,a detailed numerical simulation of the construction process is carried out.The numerical solution is compared with the monitoring data to verify the rationality of the model,and then to study the variation of the embankment settlement when the slurry shield passes through the embankment,and analyze the influence of different grouting pressures on the embankment settlement.At last,this paper summarizes the settlement control measures of the slurry shield passing through the embankment from seven aspects.The measured maximum settlement of the embankment is 21.7 mm,which is controlled within 0.5%of the height of the embankment,and a good control effect has been achieved»which can provide a reference for similar projects.