Research on Safety Control Techniques for Complex Subway Construction

The Chongwenmen subway station of Beijing metro No.5 was the first one that was constructed with mining method under exiting subway tunnel in China.Due to ensuring the operating safety of the exiting subway tunnel during the construction,the construction was very difficult and facing with high risks.Before the construction,the exiting subway structure was surveyed,and the control criteria were decided based on the survey results.By optimizing analysis,the most appropriate construction and auxiliary measures such as water decline,big pipe curtain,grouting reinforcement were selected.Meanwhile,a system of remote automatic real-time monitoring was used to monitor dynamic responses of the existing subway.When abnormal issues were found,protective measures were adopted in time.With those measures,the subway station was constructed successfully and the existing subway was running normally during and after the construction.