Economic Analysis of Reverse Construction Method of Underground Station

In order to reasonably select construction method for urban rail transit underground stations, through design and research, data analysis and engineering practice of three typical underground station construction methods, the conclusions are as follows: 1) For underground station with four floors or deeper, or structure with foundation pit deeper than 30 m, adopting cover-excavation reverse method can save construction investment by 5.3%~7.5% compared to adopting open excavation; saving by 2.3%~5.4% for three-floor underground station or foundation pit with a depth of 20~30 m; for structure of twofloor underground station or foundation pit depth less than 20 m, the civil construction investment of reverse method is close to that of open excavation, if not slightly higher. 2) Cover-excavation reverse method is recommended for four-floor underground station or deeper structure (foundation pit more than 30 m, poor geological condition and complex environment); cover-excavation reverse method is preferred for three-floor underground station or structure with foundation pit depth of 20~30 m; open excavation method is generally adopted for two-floor underground station or structure with foundation pit depth less than 20 m.