盾构近距穿越施工影响下地铁桥梁变形控制

为研究盾构下穿既有地铁桥梁结构及轨道变形规律,以北京市南水北调东干渠穿越地铁5号线工程为依托,采用对既有桥梁的数值模拟和现场监测等方法,分析了桥梁的变形规律。研究结果表明:穿越施工影响下,因盾构起始离左线轨道较近,先期左线轨道沉降大于右线,在盾构穿越桥梁后沉降量趋于一致且稳定,梁体结构最大沉降为1.76mm;隔离桩能有效地减小既有桥梁变形;数值模拟可准确地反映桥梁结构变形趋势及受影响程度。

In order to investigate the structure and track deformation law of shield tunneling through existing subway Bridges,the project that south-to-north water transfer east main canal through Beijing subway line 5 engineering as the backing.By means of numerical simulation and field monitoring of existing bridge,the deformation law of the bridge is analyzed.The results show that:Under the influence of crossing construction,the settlement of the left track is larger than that of the right track in the early stage because the shield tunneling starts close to the left track.After crossing the bridge,the settlement tends to be consistent and stable,and the maximum settlement of the beam structure is 1.76 mm.The isolation pile can effectively reduce the deformation of existing Bridges.Numerical simulation can accurately reflect the deformation trend and affected degree of bridge structure.