复合地层下泥水盾构管片上浮规律及影响因素分析

针对在盾构隧道施工中经常出现的管片上浮问题,以南昌轨道交通4号线泥水盾构过江隧道为工程依托,通过数理统计方法对泥水盾构穿越不同地层时管片上浮量进行归纳分析,探讨地层参数以及盾构掘进参数对管片上浮的影响规律。研究结果表明:在全断面砂层中掘进,管片上浮量小且上浮值变化稳定;而当进入上软下硬地层和泥质粉砂岩层,管片上浮量急剧变化,尤其是在过江段中风化泥质粉砂岩中掘进,管片上浮量最大。考虑盾构掘进参数单因素影响,随着注浆压力、泥水压力和盾构推力的增大,管片上浮量均会出现增大,而掘进速度的变化对施工期间管片上浮影响较小。在掘进过程中需要结合地层特性对管片上浮影响并且对主要掘进参数进行实时调整,在一定程度上可以实现对管片上浮的有效控制。

Research on the Floating Law and Influencing Factors of Mud-Water Shield in Composite Strata

Aiming at the problem of segment floating in shield tunnel construction, based on the project of slurry shield cross-river tunnel of Nanchang Metro Line 4, through mathematical statistics method, this paper summarizes and analyzes the segment floating amount when slurry shield passes through different strata, and discusses the influence law of stratum parameters and shield tunneling parameters on segment floating. The research results show that: when driving in the full section sand layer, the floating amount of segment is small and the change of floating value is stable; when it enters the upper soft and lower hard stratum and argillaceous silt stratum, the floating amount of segment changes rapidly, especially in the weathered argillaceous silt stone of river crossing section, the floating amount of segment is the largest. Considering the single factor influence of shield tunneling parameters, with the increase of grouting pressure, slurry pressure and shield thrust, the segment buoyancy will increase, while the change of tunneling speed has little influence on segment floating during construction. In the process of tunneling, it is necessary to combine the influence of stratum characteristics on segment floating and adjust the main driving parameters in real time, which can effectively control segment floating to a certain extent.