Automatic control of groundwater balance to combat dewatering during construction of a metro system

The construction of a metro system in groundwater-rich stratums can cause an imbalance in groundwater levels. This study presents an automatic pumping-recharge system (APRS) to maintain groundwater balance during dewatering, thereby protecting the environment. The APRS overcomes the limitations of the traditional pumping-recharge operation performed manually by workers. Further, in traditional pumping-recharge operations, a large proportion of the pumped water is wasted by draining it into the sewerage system; this is because of the lack of an efficient application for groundwater recharge. The developed APRS system includes three subsystems: i) a pressure control system, ii) an integrated process system, and iii) an intelligent electronic control system. The APRS can not only balance the groundwater system but also control the settlement during underground construction. The proposed system has been employed in the construction of a metro station in Jinan city, which has a dense distribution of spring groups. The efficiency of the APRS was verified by field observations.