Abstract: The deformation behaviors of deep excavation and its adverse impact on surrounding environment could be effectively controlled by reinforcement in the passive zone which is widely applied in actual projects. With a deep excavation for the metro station in Shanghai soft soil area as research background, the impact of reinforcement in passive zone on excavation-induced deformation was investigated by numerical simulations. Results showed that by reinforcement in passive zone, the magnitude of deformations could meet control requirements. With the increase of reinforced depth, deformations such as lateral wall deflection, ground settlement and bottom upheaval could be effectively controlled; but excessive improvement on the magnitude of E₅₀^ref for reinforced soil had little impact. The effect of controlling excavation deformation by reinforcement of entire basal soil is obviously superior to that by reinforcement along the diaphragm wall under equal condition.

Key words: soft soil, deep excavation, soil reinforcement in passive zone, excavation deformation, secant modulus, reinforcement of entire basal soil, reinforcement along diaphragm wall