Abstract: The metro deep excavation sites are commonly located in the highly urbanized area with complicated conditions. The stress and deformation of the deep excavation supporting structures are frequently affected by the adjacent environments and are the usually the focus of the construction engineering projects. This paper presents a numerical analysis results for the deep excavation for the Maozhutang Station of Changsha Metro No.5 Line. This deep excavation is close to a high slope and was numerically simulated by using a finite difference software FLAC^3D. The stress and deformation in the supporting structures in the excavation progress were simulated and the results were compared with the construction monitoring data. The following conclusions can be obtained based on the numerical analysis and measured data: a maximum of 8.0 centimeter of heave was observed at the bottom of the excavation and the accumulative subsidence surrounding the excavated area was 2.23 centimeter; At the initial stage of the excavation, the top of the supporting structure tilted towards the excavation and a “bow” shaped deformation in the supporting structure was observed in the later phase of the excavation. The maximum accumulated horizontal deflection measured was 1.67 centimeter in an inclinometer. The numerical analysis predicted the same deformation shape, but the maximum lateral deflection was slightly less than the measured value. The bending moment in the concrete struts increased gradually and reached to the maximum value and gradually stabled when the second layer of steel struts were applied. The axial stress in the steel strut changed differently with the incremented excavation depths.

Key words: high slope, deep excavation for foundations, stress and deformation, numerical simulations