浅埋大跨粉细砂层地铁车站洞桩法半逆作施工技术

Semi-Reverse Construction Technology of PBA Method for Shallow Buried Large-Span Subway Station in Silty Fine Sand Layer

石家庄市轨道交通3#线东二环南路站,长204.8 m,两柱三跨地下三层结构,下穿双层交叉城市快速路,为浅埋地铁车站,车站主体穿越粉细砂层,采用暗挖施工。通过对浅埋大跨粉细砂层地铁车站暗挖施工研究,针对车站工况,在传统的浅埋暗挖施工的基础上结合盖挖法,通过导洞、扣拱及桩等技术的有机结合,发挥盖挖与分步暗挖各自优势,创新采用双层导洞组合洞桩法半逆作施工技术,有效解决了浅埋大跨车站穿越粉细砂层施工难题,保障了既有快速路正常运营,实现了车站开挖安全施工,效益显著。

The line length of Shijiazhuang Rail Transit Line 3 East Second Ring South Road Station Project is 204.8 m with a two-column,three-span underground three-story structure.The project passes under the double-decker cross-city expressway.The station is a shallow buried subway station.The main body of the station passes through the silt and fine sand layer,and the construction is carried out by underground excavation.In view of the construction situation of the station,on the basis of the traditional shallow buried underground excavation construction technology and combined with the cover excavation method,this thesis studies the use of underground excavation construction technology in shallow buried large-span silty and fine sand layer subway stations.The organic combination of mature technologies such as pilot tunnel,buckle arch and pile,giving full play to the respective advantages of cover excavation and step-by-step concealed excavation,and innovatively adopting the semi-reverse construction technology of double-layer pilot tunnel combined PBA method,effectively solves the construction problem of shallow buried large-span station through the silt and fine sand layer,which not only ensures the normal operation of the existing expressway,but also realizes the safe construction of station excavation,and the benefits are significant.