通过对杭州地铁4号线2次近距离下穿地铁1号线施工过程沉降监测数据的分析,探讨盾构施工对既有隧道变形的影响规律.结果表明:既有隧道变形与盾构掘进的相对位置密切相关;盾构小角度穿越时对既有隧道沉降影响较大;多次穿越同一既有隧道时,不仅要加强对既有隧道的监测,同时也要对新建隧道进行变形监测,以便及时调整土舱土压力、注浆量等施工参数,防止既有隧道产生过大变形.%To unveil the influence of shield construction on adjacent tunnels,the paper analyzed the data collected in the monitoring and measuring of No. 1 Metro Line in Hangzhou amid the construction of No. 4 Metro line,which passes under the former twice with small spacing apart. The results showed that the deformation of existing tunnel was closely linked to its relative location to the shield operation,or to be more specific if the operation was carried out by a small angle to the existing line,the settlement induced may increase by a large margin. In case of multiple under passing,monitoring shall be tightened up for both existing tunnel and the ongoing construction,so as to better handle the earth pressure and the grouting volume in avoidance to over-deformation.
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