MONITOR AND ANALYSIS OF RAILWAY LINE SETTLEMENT CAUSED BY CONSTRUCTION OF SUBWAY TUNNELS BENEATH A CLUSTER OF EXISTING RAILWAY LINES IN THE NANJING RAILWAY STATION
Abstract：Constrained by the Nanjing railway station，the Nanjing subway station of Nanjing metro No.1 is subdivided into three parts as following：(1) the southern cutting part；(2) the northern cutting part；and (3) the connecting tunnels part. The connecting tunnels as a part of main structure for the Nanjing subway station are just beneath a cluster of existing railway lines of the Nanjing railway station，which includes two separated tunnels. The connecting tunnels constructed with mining method have the features of large span，shallow coverage，and little distance between the two lines. Railway line settlement must be restricted to insure the safety of railway lines during construction. A large numbers of settlement points are placed on the railway roadbed and the beam support foundation. The railway roadbed settlement induced by tunnels construction is discussed and the settlement monitored results indicate that the rail reinforcement method and the connecting tunnels construction technique are reliable. At the same time，with the analysis of settlement data，some suggestions on similar engineering construction are presented.
