Abstract: The deformation of a double-row-piles supported deep excavation project in the weathered slate area was numerically simulated by using finite element method. The ground subsidence surrounding the excavated area, lateral deflection as well as the stress in the supporting structure during the entire excavation process were evaluated and compared with the construction monitoring data in order to provide an optimized excavation sequence. The results indicate that, in the excavation process in the weathered slate area, the ground settlement within a distance of 6.5 to the excavated area and lateral deflection at the top of double-row piles should be monitored with more attentions; Further, large bending moments were observed in the front row piles 4.5 m from the top and the and 16 m from the pile top in piles in the rear row.

Key words: Deep Excavation, Weathered Slate, Double-Row-Piles