关键词: 软土地区, 临地铁深基坑, 伺服式预应力混凝土支撑, 基坑变形控制

Abstract: With the development of subway, the unloading of the deep excavation will adversely affect the adjacent subway tunnel, which even may cause the local damage to the tunnel structure. Based on a project in Qingpu District of Shanghai, this paper introduces the application of servo prestressed concrete support in the deep excavation near a subway in soft soil area. The engineering practice shows that the servo prestressed concrete support has obvious control effect on the lateral displacement of the supporting structure, which can reduce the lateral displacement of the retaining structure by 30%~40%. By using the servo prestressed concrete support technology to actively apply axial force, the deformation of retaining wall can be accurately controlled, and the influence on sensitive buildings (structures) such as rail transit is reduced. In the implementation process of the servo prestressed concrete support, the key monitoring data such as retaining inclination measurement and support axial force, load them step by step, and dynamically adjust the prestressed loading value according to the monitoring results are presented.

Key words: Soft Soil Area, Deep Excavation Near Subway, Servo Prestressed Concrete Support, Deep Excavation Deformation Control