The Xiqing Road Tunnel of Tianjin West Railway Station Hub crosses over the existing tunnel boxes of the operating Tianjin Metro Line 1. The bottom plate of the Xiqing Road Tunnel is just 0.3 m away from the upper plate of the existing tunnel boxes

so the deformation of existing metro tunnel due to construction should be controlled strictly. The design bring forward some pertinence construction plans and measures

including ground improvement

excavation in sections and back pressure of heaped load timely. Base on the analysis of monitoring data during the construction and excavation of anti-floating piles and triaxial cement mixing pile of Xiqing Road Tunnel adjacent to the existing metro tunnel

and the corresponding deformation rules and characteristics in the different stages are summarized. The measured results show that the construction of bored piles adjacent to the existing metro tunnel could lead to the tunnel settlement

while the excavation could cause the heave of the tunnel. Due to excavation in sections

Back pressure of heaped load as well as the observational method

the vertical deformation of existing tunnel caused by excavation and the different deformation between the two adjacent boxes can be controlled effectively.