新奥法施工近距双线浅埋隧道围岩变形特性研究

为揭示新奥法施工近距双线浅埋隧道围岩的变形特性,依托某市地铁隧道工程为背景,采用理论分析、数值模拟、现场测试等相结合的方法,分析近距双线浅埋隧道采用新奥法施工过程中的地表沉降、拱顶位移及围岩收敛规律。研究结果表明:隧道开挖面卸载是围岩发生变形的主要诱因;近距双线隧道开挖围岩变形存在叠加,主要叠加区域位于双线隧道中线连接区域,相比单线开挖同位置变形最大增量达45%;由变形预测结果可知,地层变形在建设期基本完成,约占预测10年变形总量的85%以上。

Study on Deformation characteristics of Surrounding Rock near Double-line Shallow Tunneling by NATM

To reveal the deformation characteristics of surrounding cock due to NATM construction near shallow tunnel,surface subsidence,vault displacement and surrounding rock convergence regularity of shallow buried tunnel are analyzed through theoretical analysis,numerical simulation and field test method with reference to a urban metro tunnel. The research results show that the surface of tunnel excavation unloading is the main cause of surrounding rock deformation; close double tunnel excavation of surrounding rock deformation is superimposed mainly in the midline connection region of double-line tunnel with maximum deformation reaching 45% of the single tunnel excavation at the same position. The pre deformation measurement results show that the stratum deformation is basically ended in the construction period,which accounts more than 85% of the total deformation of 10 year prediction.