Abstract: With the rapid development of urban underground rail transit, there are more and more deep excavation projects to be constructed adjacent to the existing rail transit system. This paper presents a case history of the support design of a deep excavation near Wuhan Metro No. 2 Line. The effect of the “threerows of pile plus passive retained soil zone method on the existing live operating metro line is evaluated. The results indicated that, both the vertical and lateral deflections of the existing metro structures were less than 10 millimeters. The maximum stress in the metro structures were also within the allowable limits. Based on the evaluation, it is concluded that the safety of the existing metro structures could be warranted.

Key words: deep excavation construction, three-rowsofpiles plus passive retained soil zone, existing rail transit, numerical analysis