关键词: 地铁车站, 盖挖逆作法, 钢管混凝土柱, 垂直度, 偏差, 置换法

Abstract: For a metro station constructed with the cutandcover topdown method, if the perpendicularity of the concretefilled steel tubular columns does not meet the requirements of relevant specifications, the perpendicularity deviation must be corrected. The perpendicularity deviations of the concretefilled steel tubular columns of the first underground floor to the third underground floor toward  the horizontal crosssection direction of the station reach 114, 254, and 375 mm, respectively, those toward longitudinal direction reach 44, 68, and 93 mm, respectively, which is beyond relevant requirements, showing that concretefilled steel tubular columns should be replaced. The main measures adopted are as follows: (1) temporary support is provided for the replacement structure by the joint support of concrete and steel tubular columns; (2) when removing the concretefilled steel tubular columns, a combination of static and manual removal is used to retain the original beams and steel bars in the plate; (3) the newlyadded steel pipe top reinforcement ring and the original reinforcement ring of column top of the first underground floor are tightened, bolted, and welded to ensure the reliability of the connection; and (4) the automatic deformation and strain monitoring should be conducted during the whole construction process. The practice shows that the replacement scheme is reasonable and feasible.

Key words: metro station, cut , and , cover top , down excavation method, concrete , filled steel tubular column, perpendicularity, deviation, replacement method