盾构浅覆土下穿河流施工地层稳定性研究

Study on the Construction Formation Stability of Shield Tunneling Under River with Shallow Soil Covering

盾构浅覆土穿越河流施工极易发生地层失稳,造成较大工程风险。依托宁芜铁路扩能改造工程,开展盾构机浅覆土条件下穿河流换填地层稳定性研究。基于工程参数建立三维有限元模型,模拟河道换填加固后盾构施工诱发地层的位移过程,分析换填地层扰动变化规律;根据换填混凝土以及河道地层物理特性,采用解析法和数值分析法开展盾构施工参数对地层稳定性影响研究。研究结果可为后续盾构浅覆土下穿换填河流地层稳定性控制提供理论依据和工程应用价值。

In the construction process of shield crossing river with shallow soil covering,stratum instability is easy to occur,resulting in greater engineering risk.Relying on the expansion and reconstruction project of Nanjing-Wuhu Railway,this paper studied the formation stability of the underpass river replacement with shallow soil covering by shield tunneling machine.Based on the engineering parameters,a three-dimensional finite element model was established to simulate the displacement process of the strata induced by the construction of the reinforced backing structure and analyze the change law of disturbance of refilled strata.According to the physical characteristics of refilled concrete and channel formation,the influence of shield construction parameters on formation stability was studied by analytical method and numerical analysis method.The research results provide theoretical basis and engineering application value for the stability control of the strata in the stream under the shield shallow soil covering.