Winter Anti-freeze and Insulation Scheme for Zhengzhou Metro Underground Station Water Supply and Drainage Pipelines

Objective During winter in northern China, water supply and drainage pipelines located at ventilation ducts and the entry/exit that connect urban rail transit underground stations to the outdoors are prone to freezing and bursting. It is necessary to develop a scientific and reasonable winter anti-freeze and thermal insulation scheme for metro station pipelines, determining the appropriate coverage of electric heat tracing system. Method Using an underground station on the suburban line of Zhengzhou Metro as example, seven typical monitoring points at the station entry/exit and piston ventilation ducts are selected. The ambient temperature at the seven points are monitored and analyzed. Based on a well-trained neural network model, two most unfavorable working conditions are selected, under which comparisons are made between the actual and simulated ambient temperatures at each monitoring point. COMSOL Multiphysics software is used to simulate the water temperature variation patterns within water supply and drainage pipelines of various diameters in specific areas. Result ＆ Conclusion A configuration scheme of winter anti-freeze, insulation, and electric heat tracing system for water supply and drainage pipelines in Zhengzhou Metro underground stations is proposed. Compared to existing solutions, the proposed scheme reduces the configuration scope of electric heat tracing system, lowers the construction investment, and decreases the operation and maintenance costs during the operation phase.