浅埋暗挖在南水北调穿京石高速公路中的应用

Application of shallow-buried excavation in penetration of Beijing—Shijiazhuang Expressway at South-to-North Water Diversion Project

PCCP管道工程穿京石高速路浅埋暗挖是北京市南水北调中线干线工程关键节点之一。管道穿越京石高速公路隧洞双联洞结构,属于超浅埋隧道,且隧道处于砂壤土中,施工时不仅要保证隧洞内安全作业,还要保证京石高速路的安全畅通。大管棚施工及小导管超前注浆施工作为浅埋暗挖作业的超前支护措施,CD法暗挖施工作为暗挖作业强支护措施,使洞口及隧洞顶部覆土更稳定,避免了大面积的塌方,降低了施工风险,确保了施工的安全。本文详细论述了该工程施工方案及施工技术措施。

Shallow-buried excavation during PCCP pipeline project penetration through Beijing—Shijiazhuang Expressway is one of key nodes in Beijing South-to-North Water Diversion Mid-Line Trunk Project. The pipeline penetrates through tunnel double-hole structure of Beijing—Shijiazhuang Expressway,it belongs to shallow-buried excavation tunnel. The tunnel is located in sand soil. Safe operation in the tunnel should be guaranteed during construction on one hand,and safe and smooth Beijing—Shijiazhuang Expressway should be ensured on the other hand. Large pipe shed construction and small conduit advanced grouting construction are regarded as advanced support measures of shallow-buried excavation operation.CD method buried excavation is regarded as strong support measure of buried excavation. More stable soil is arranged in the opening and at the top of tunnel,thereby avoiding large area collapse,reducing construction risk,and ensuring construction safety. In the paper,construction plan and construction technical measures of the project are described in detail.