被动区土体加固对深基坑变形影响的研究

被动区土体加固能有效地控制基坑开挖引起的变形、保护基坑周边环境,在实际工程中得到广泛的应用。对上海软土地区某地铁车站深基坑工程进行数值模拟,系统地研究了不同土体加固形式对基坑变形的影响。研究结果表明:该工程采取的坑底加固措施使得基坑变形满足变形控制标准;增大土体加固的深度能显著地减小围护结构侧向位移、地表沉降和坑底隆起;而过度地增大加固土体的割线模量E_(50)~(ref)对控制基坑变形的效果甚微;在同等条件下,满堂加固控制基坑变形的能力明显优于裙边加固。

Impact of Soil Reinforcement in Passive Zone on the Deformation Behaviors of Deep Excavation

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 Eref50 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.