大直径泥水平衡盾构下穿既有地铁结构预加固方案研究

为了保证北京地铁10号线和13号线换乘车站(知春路车站)在京张高铁清华园隧道下穿施工过程中的结构安全性和运营稳定性,采用数值模拟对3种预加固方案(水平旋喷桩、管幕和小导管注浆)下既有地铁车站结构的变形和受力进行分析。采取预加固措施后,地铁车站结构的变形和受力都得到了有效控制。结合数值模拟分析的结果,同时从地层适用性、加固效果、环境影响、施工工艺、工程造价、结构变形和受力等多方面对3种预加固方案进行对比分析。以既有地铁车站所处环境和重要性等级为基础,建议选择小导管注浆预加固方案,该方案既能保证下穿施工过程中既有地铁车站结构的安全,又能降低工程造价。

Study on Pre-reinforcement Measures of Large-diameter Slurry Balance Shield Beneath Existing Subway Structure

In order to ensure the structural safety and operational stability of the interchange station( Zhichunlu Station) for Beijing Subway Line 10 and Line 13 during the construction of Tsinghuayuan Tunnel in the Beijing-Zhangjiakou High-speed Railway,three kinds of pre-reinforcement measures( horizontal rotary jet grouting pile,pipe curtain and multi-layer small duct grouting) were used for numerical simulation. The deformation and stress of the existing subway station structure under these three kinds of pre-reinforcement measures were studied and analyzed. It was found that the deformation and stress of the subway station structure were effectively controlled after the pre-reinforcement measures were taken. Combined with the results of numerical simulation analysis,the three pre-reinforcement measures were compared and analyzed from the aspects of stratum suitability,reinforcement effect,environmental impact,construction technology,engineering cost,structural deformation and stress characteristics. Based on the environment and importance level of the existing subway station,it is recommended to select the small duct grouting pre-reinforcement scheme,which can both ensure the safety of the subway station structure and reduce the construction cost during the construction process.