This research carried out investigations on the hydrogeological characteristics of inflow groundwater into subway station in South Korea. It is well known that the behaviour of groundwater around urban area has greatly affected risks on ground subsidence as well as underground structures. Especially, there are many cases of urban sinkhole due to a large volume of groundwater generated during the construction and operation of subway system in South Korea. There are 16 lines of subway with 481 stations in 6 cities in South Korea, and the half of them are placed in Seoul, the capital of South Korea. About 10,000 m3/day of groundwater was inflow into subway stations in Seoul. In order to investigate the characteristics of inflow groundwater, a test-bed station was monitored for several parameters such as the volume of inflow, water temperature, and electric conductivity, etc. for several months, With geological properties of ground and environmental factors such and rainfall and surface water near the station, the station, the monitoring data was analysed to estimate their correlation and abnormal behaviour. Further studies are ongoing to setup a real-time inflow groundwater monitoring and risk assessment and risk assessment system, which would prevent risks on the underground near subway and its infrastructures.

inflow groundwater; subway; ground subsidence; monitoring; tunnel