浅埋区间盾构上部基坑开挖保护施工技术

Construction Technology of Excavation Protection for Foundation Pit Above Shield in Shallow Buried Section

为降低基坑开挖过程中对既有盾构隧道变形的影响,保证地铁盾构区间结构的质量与安全,利用有限元三维分析的计算方法,并结合相似工程的施工经验,制定了以碎石粉反压+内支撑+分条开挖为主要手段的隧道保护措施,有效地控制了隧道在上方基坑开挖后的竖向位移量。通过在工程中的运用,证明了该保护方法的有效性,可为类似工程提供借鉴。

To reduce the influence of foundation pit excavation on the deformation of the existing shield tunnel and ensure the quality and safety of the subway shield section structure,the tunnel protection measures are formulated by using the 3 D finite element analysis calculation method and combining with the construction experience of similar projects,with the main means of gravel powder back compact+internal support+sectional excavation.It effectively controls the vertical displacement of the tunnel after the excavation of the above foundation pit.The engineering application proves the effectiveness of the protection method,which can provide reference for similar projects.