为解决改扩建车站面临的新增半幅车站与既有基坑水土压力不平衡、两端延伸基坑宽度较大、换乘节点交通导改复杂等问题，通过对各区块基坑做详细比选分析，并结合考虑施工过程、永久使用阶段各种作用组合和结构型式转变的数值分析结果，确定了改扩建方案。主要结论如下： 1）既有半幅基坑已开挖至底部，新建半幅基坑应采用盖挖逆作法施工； 2）两端延伸基坑应采用明盖挖相结合的工法，并采用锚索支护，盾构接收范围内锚索采用可回收工艺； 3）换乘节点处基坑采用盖挖逆作法施工； 4）盖挖段竖向支撑构件应采用临时立柱与永久立柱结合的钢管混凝土，柱下设中间桩基础（兼作抗拔桩）。最后，通过时程分析法验证了车站主体结构在E3地震作用下能够满足抗震性能Ⅱ的要求。

During the rehabilitation of an existing metro station, a series of problems occurred, such as the water and soil pressure imbalance between the newlyadded semirange station and the existing foundation pit, large width of the foundation pit extended at both ends, and complex traffic diversion and reconstruction of transfer node. Accordingly, a set of relatively perfect rehabilitation scheme is formed through detailed comparison and analysis of foundation pits in each section based on numerical analysis results considering various action combinations and structural type transformation in construction process and permanent use stage. The main conclusions are drawn as follows: (1) The existing semirange of the foundation pit has been excavated to the bottom, thus the new half should be constructed by the cutandcover topdown method. (2) The extended foundation pit at both ends should be constructed by the combination of open cut and cutandcover methods, and the anchor cable support that can be recycled should be adopted. (3) The foundation pit at the transfer node should be constructed by the cutandcover topdown method. (4) The concretefilled steeltubular column combined with temporary column and permanent column should be adopted for the vertical support components of the cutandcover section, and the middle pile foundation (also used as uplift pile) shall be set under the column. In addition, the timehistory analysis method is used to verify that the main structure of the station can meet the requirements of seismic performance Ⅱ under levelE3 earthquake effect.