Objective With climate change, the extremeness and suddenness of flood disasters increase the inundation risk of ground facilities in metro systems. On one hand, existing studies on flood protection for metros at home and abroad mainly focus on the development of water-blocking equipment and risk assessment. On the other hand, in China, the vertical design for flood protection of metro ground facilities usually adopts the method of uniformly increasing the safety freeboard, which has deficiencies in both design method and flood protection capacity improvement. Therefore, it is necessary to establish a quantitative method for the above vertical flood protection design and propose a scheme to improve flood protection capacity.

Method In view of regional characteristics and flood characteristics, based on the principle of integrated flood and waterlogging management, factors such as regional ground elevation, urban flood control capacity, regional waterlogging drainage capacity, and plot drainage capacity are comprehensively taken into account. A coupled simulation technology integrating road network, pipe network, and river network (the "three-network integration") is employed to simulate and evaluate the waterlogging control capacity of the area where ground facilities are located, quantify the characteristic parameters for flood prevention and inundation elevation, and ultimately establish a quantitative vertical design method for metro ground facilities flood protection along with differentiated schemes to improve flood protection capacity.

Result & Conclusion The quantitative method for vertical flood protection design and the scheme for improving flood protection capacity of metro ground facilities can realize the quantitative calculation of inundation elevation for flood protection adapted to spatial differences. It can be used for vertical design in scenarios such as the construction and renovation of metro ground facilities and the integrated construction of surrounding plots, enhancing the flood protection capacity of metro ground facilities and the overall waterlogging control capacity of the metro system.