| China is a country with frequent floods and floods.The disaster caused by floods seriously threatens people’s lives and property.The influence of backwater effect of flood on the flood level of river is one of the most serious flood disasters.In view of the problem of river backwater jacking,this paper focuses on the occurrence of jacking in the rivers crossing the Nenjiang River and the Second Songhua River(for short Ersong)in the Songhua River Basin.Based on the observational floods at the Dalai Station and Fuyu Station,choose the typical years from the history data and design the floods with different frequencies,which is simulated using the MIKE one-dimensional hydrodynamic model,and the combination of historical measurement and model simulation results is used to analyze the law of the jacking.The main research contents and achievements of this article include:(1)Based on the measured flood data in the study area,the analysis of top impact was conducted.According to the historical flood data,the typical flood years of Nenjiang and Ersong floods were selected based on the historical flood data of Dalai Station in Nenjiang and Fuyu Station in Ersong,and the relationship between flood level and topography was identified based on the unusual changes in water level and flow relationships at the two stations during a typical year.Calculate the amount of support.The results show that Nenjiang River is more susceptible to the impact of the Ersong flood.When the flow at Dalai Station is relatively small,the maximum amount of top impact can reach more than 4m.(2)According to the fact that the measured flood data in the study area were lower than the 20-year flood,the model simulation was used to generated high-frequency floods in excess of 20 years,and carried out top-load impact analysis.Due to the fact that the flood frequency of historical data is lower than 20 years,the impact of high frequency flooding can’t be analyzed.Therefore,in order to analyze the influence of the flooding more comprehensively,This paper uses MIKE11 to establish a one-dimensional hydrodynamic model and design to simulate the flooding process of 20-,30-,35-,and 50-year floods at the two stations,and to analyze the process of flooding at Dalai station..(3)According to the analysis of the historical measured flood and simulated flooding impact,the law of the topography was explored.By analyzing the size of flooding at the same frequency and different frequencies,and the change of dumping volume under different flow ranges,is summarized.the law of backwater effect.The results show:i)when the flow rate between Fuyu station and Dalai station is higher than 2 at the low flow rate of Dalai station,the phenomenon of backwater jacking at Dalai station will occur,and the maximum height of the jackscrew can reach more than 4m.ii)When the Nenjiang Dalai station flow reaches more than 3000m~3/s,the impact of flooding at the ersong will no longer be serious,and the amount of jacking will be less than0.5m.iii)When the Nenjiang Dalai station,the flow reaches 5000m~3/s.after the above,the impact of the flood on the ersong reaches a maximum of 0.4m,and in most cases it is less than 0.3m,and with the increase of the flow at the Fuyu Station,the jacking capacity will no longer increase. |
