Abstract: This paper presents a case history of a deep excavation near an existing regional subway tunnel. The entire excavation and supporting process are three dimensionally simulated throughout a numerical model by using the commercial software Midas GTS NX. The influence of excavation on the ground subsidence, vertical and horizontal deformation of the supporting structure and on the deformation of lining structure of the existing tunnel are analyzed. The results show that the maximum settlement of the surrounding surface caused by the excavation is 8.20 mm, the maximum horizontal deformation of the enclosure structure is 10.86 mm, and the maximum vertical deformation is 3.28 mm, all within the specification limits. The maximum horizontal deformation of the existing lining structure is 3.88 mm, and the maximum vertical settlement is 2.28 mm. All deformations meet the limit requirements for safe operation of the interval tunnel. 

Key words: Deep Excavation Support, Numerical Simulation, Subway Tunnel, Deformation