Abstract: This article presents a case history project of a 3-story underground station of Fuzhou Metro Line 4. The construction supporting system of a 26.1 meters deep excavation is introduced. The horizontal displacement of the diaphragm wall, the vertical settlement of the steel soldier pile and the axial force of the support are monitored. The monitoring data show that, during the excavation of a standard section, the soldier pile bulge with the excavation depth and time. As the soldier pile bulges, cracks appear at the junction of the soldier pile and the first concrete supporting waler. These cracks have a negative impact on the distribution of axial force and the stability of the horizontal supporting system. The artesian water in the cracks of the soil also has a significant impact on the uplift of the soldier piles. By analyzing the deformation data and patterns of the excavation supporting system during the excavation, it is explored that shortening the excavation exposure time is the best way to reduce the deformation of the excavation supporting system.

Key words: Deep Excavation, Deformation of Excavation Supporting System, Artesian Water, Shorten Excavation Exposure Time, Best Option