Abstract: The causes and characteristics of ground flood invading into underground space are analyzed in terms of internal and external factors to obtain the flooding rule and prevention mechanism. Research result suggests that vulnerable external environment is the primary factor of flood invading into underground space. Defensive measures and capabilities of underground space itself are closely related to disaster loss. Since ground flood intrudes in a variety of paths and means with many uncertain factors and complex hydraulic characteristics yet no clear unified rules to follow, countermeasures for important and large underground space must be determined through combination of numerical simulation and physical modeling. In addition, the arrangement of drainage system should be based on flow characteristics analysis, and drainage facilities should be located along the water flow path near the flood invasion site in large scale and quantity. The results could be referenced for the choice of rational countermeasures of flood prevention.

Key words: urban underground space, ground flood, flow characteristics, flooding cause, flooding characteristics, flood control environment