Flood Inundation Analysis of Existing Small Culverts and Study of Flooding Capacity

In order to clarify the mechanism of inundation water damage of existing railway small culverts, and reduce the secondary water damage brought by inundation water damage to the railway. The article takes the K477+698 culvert of Lanzhou-Xinjiang Railway as an example, establishes the hydrological model through SWMM, simulates the inundation process of the railway small culvert, and analyzes the rainfall runoff under different return periods, studies the flooding capacity of the culvert, and obtains the following conclusions: the hydrological model simulates the inundation water damage process of the K477+698 culvert of Lanzhou-Xinjiang Railway and the actual measured data are close to each other, and the analysis is applicable for the flooding inundation of small culvert. In addition, When the culvert is not inundated, the water level of the culvert is positively correlated with the rainfall duration and the return period, and when the culvert is inundated, the inundation duration is positively correlated with the rainfall duration and the return period. Finally, after the inversion trial calculation, the critical inundation drop for the inundation of K477+698 culvert is 3h and 6h. The critical inundation rainfall for water damage is 20.14mm and 21.41mm respectively, which provides reference for the determination of flooding capacity of existing small culverts.