城际铁路盾构联络通道冻结法施工技术

Freezing Method Construction Technology of Shield Connecting Passage in Intercity Railway

以珠机(珠海市区—珠海机场)城际铁路橫琴隧道金融岛车站—3号工作井区间3#联络通道(与泵房合建)为工程背景,针对联络通道冻结法施工形成的形状复杂的冻土帷幕结构,利用FLAC 3D对冻结法施工进行了数值模拟,并与现场监测数据进行对比分析,得出冻结帷幕的变形特性、应力分布特性以及开挖造成的隧道周围管片应力的重新分布情况。研究结果表明:联络通道开挖前对通道内土体预加固能有效改善拱顶和拱底的受力状态;喇叭口是整个冻土帷幕的最薄弱处所,施工中须特别注意;联络通道开挖容易使主隧道管片处于受拉状态,且拉应力多分布在开口环的对侧。

Taking 3 connection passage(ioint construction with pump house)of Hengqin tunnel Finance Island Station to 3^#work well interval section in Zhuji(Zhuhai City-Zhuhai Airport)intercity railway as the engineering background,FLAC 3D was used to simulate the freezing method construction according to the complex-shaped frozen soil curtain structure formed by freezing method construction of connecting passage,and the deformation characteristics,stress distribution characteristics of frozen curtain and segment stress redistribution around the tunnel caused by excavation were obtained by comparisons and analysis with f ield monitoring data.The results show that pre-reinforcement of soil in connecting passage before excavation can effectively improve the stress state of arch roof and arch bottom,the bell mouth is the weakest part of the whole frozen soil curtain and special attention should be paid to it in construction,the main tunnel segment is easy to be tensioned by the connecting passage excavation,and the tension stress is mostly divided on the opposite side of the split ring.