Jacking characterization of compound flooding on drainage network based on physical model experiment and numerical...

The capacity of the coastal drainage network is significantly reduced by the jacking effect of high tide and river levels under compound flooding, but the mechanism of jacking effect on drainage network is not fully understood. In this study, the jacking effect of high tide and river levels is analyzed based on physical and numerical models using Haikou City as an example. A physical model for simulating compound flooding is constructed based on kinematic similarity, dynamic similarity and geometric similarity, and a numerical simulation model is constructed based on the PCSWMM model. The process and characteristics of jacking effect under high tide and river levels and the flow inter-feedback between tide-river-drainage network are evaluated using physical and numerical models coupled with water tracer method. The results show that the physical and numerical models constructed in this study have high simulation accuracy. The influence extent and intensity of the jacking effect on the drainage network will show a weakening trend with the increase of rainfall intensity, and the percentages of pipeline affected by jacking effect under the 50-year rainfall and 20-year rainfall are 52.6 % and 60.9 %, respectively. The jacking effect of high tide level is more obvious at downstream outfall, and the jacking effect of high tide and river levels interact with each other and show an inverse correlation. This study provides a theoretical basis for quantifying the jacking characterization of high tide and river levels on drainage networks and the occurrence mechanism of compound flooding.