为确保始发阶段盾构近距离安全上跨既有运营隧道,在分析工程重难点的基础上,首先,对盾构上跨施工控制措施进行介绍 并结合施工参数控制情况对上跨措施的效果进行分析,然后,对既有运营隧道的变形规律进行分析。 研究结果表明: 1)通过调整 始发基座与盾构隧道轴线坡度一致,并在洞门钢环处焊接导轨,确保了盾构按照设计坡度上坡始发; 2)向盾壳四周注入克泥效,能 够润滑盾壳,减小推力,从而减轻对既有隧道的扰动; 3)盾构刀盘进入上跨段前,既有隧道产生向上和向盾构掘进方向2个方向的 位移,随着盾构重心通过既有隧道,竖向变形逐渐回弹,并在盾尾脱出后逐渐趋于稳定; 盾构掘进方向变形在刀盘位于隧道正上方 时开始迅速增加,在盾尾脱出后迅速趋于稳定。

The safe shield overcrossing adjacent existing operation tunnel during launching should be guaranteed. Hence, the key and difficult points of the project are analyzed, the construction control measures for shield overcrossing are introduced, the overcrossing effect is analyzed according to the control of construction parameters, and the deformation law of existing tunnel is analyzed. The analytical results show that: (1) The successful shield launching according to design can be effectively ensured by adjusting the launching base to be consistent with the slope of shield tunnel axis and welding the guide rail at the steel ring of the portal. (2) By injecting lubrication material, clay shock slurry, to the shield, the thrust force can be reduced, and further the disturbance to the existing tunnel can be reduced as well. (3) The existing tunnel displaces towards upside and tunneling direction before shield cutterhead crosses; after the gravity center of the shield overpasses the existing tunnel, the vertical deformation of the existing tunnel reduces and becomes stable after the shield tail passes; the deformation of the existing tunnel towards tunneling direction increases sharply when cutterhead is right above the tunnel, and becomes stable after the shield tail passes.