广州地铁广佛线盾构隧道穿越桥梁桩基施工技术

如何在地铁盾构法隧道穿越既有桥梁桩基时，既能确保工程自身结构安全，又能保证桥梁结构的安全及功能的正常发挥，是一个必须要认真面对的课题。结合广州地铁广佛线沙涌站至沙园站盾构区间隧道下穿沙涌桥桩基的具体情况，重点介绍通过采取在洞内对桩底预留基岩的处理、桥桩与二次衬砌的连接及截桩等施工方法及技术措施，成功地将隧道二次衬砌转化为桥桩的环形托换梁，完成洞内桩基处理以及盾构空推通过的技术要点。对监测数据的对比、分析说明了该方法的可行性及合理性，为盾构下穿既有桥梁桩基的施工提供参考与借鉴。

A Case Study on How to Deal with Existing Bridge Piles in Shield Tunneling

The shield machine came across existing bridge piles while boring from Shayong station to Shayuan station of the Guangzhou～Foshan line of Guangzhou Metro. It was of great importance to ensure the structural safety of the tunnel and the safety and normal function of the bridge. The following countermeasures were adopted to deal with the existing bridge piles: 1) The tunnel section was excavated by the mining method; 2) The reserved bedrock underneath the existing bridge piles was reinforced from inside the mined tunnel; the existing bridge piles were then properly connected to the secondary lining of the mined tunnel before the piles inside the tunnel were cut off; 3) The shield machine went through the mined tunnel and the segments were erected. The analysis on the monitoring data demonstrated that the countermeasures used here were feasible and rational. This paper provides reference for similar projects in the future. 