大断面长距离通道冻结加固设计与开挖施工方案研究

Freezing Reinforcement Design and Excavation Construction Scheme of Large-section and Long-distance Tunnel

针对人工冻结法在大断面长距离隧道工程中应用经验不足的现状,以广州地铁11号线云大区间1号横通道冻结工程为例,介绍了该工程的冻结加固设计方案与大断面开挖施工方案,1号横通道分两阶段冻结,采用外圈筒形冻结壁形式,使横通道外围冻结壁范围内土体冻结加固形成高强度的冻土帷幕,开挖区域形成弱冻结区,采用矿山法进行横通道开挖支护施工,依据冻结孔布设规则,1号横通道分成4个开挖区域,依次自上而下水平开挖,施工过程中需根据掌子面地层情况进行超前加固,按此方案实施后,该工程已安全顺利完成。

The application experience of artificial freezing method in large section and long distance tunnel engineering is not enough.Taking the freezing project of the No.1 cross passage in Yuntai Garden Station-Dajinzhong Station section of Guangzhou subway line 11 as an example,the freezing reinforcement design scheme and excavation construction scheme of the large-section and long-distance tunnel are introduced.The freezing of the No.1 cross passage is performed in two stages.The frozen wall in outer ring of the No.1 cross passage is in the form of cylindrical.The soil in the frozen wall of the cross passage is frozen and strengthened to form high strength frozen soil curtain.Weak frozen zone is formed in excavation area.The mining method is used to excavate and support the cross passage.According to layout rules of the freezing hole,the cross passage is divided into four excavation areas.Horizontal excavation is adopted from top to bottom in turn.In the process of construction,advance reinforcement should be carried out according to the ground condition of the tunnel face.After the implementation of this scheme,the project was safely and successfully completed.