| Water resource is a very important energy source in our country,for full use of hydropower resources,our country has built reservoirs of about 98000.Dam has brought many benefits to our life,but the dam when under the ultra frequency flood,earthquake damage,such as dam risk will be exist.When the dam burst,the burst flood wave will quickly advance downstream.The burst flood has the characteristics of large discharge,short duration and high water level.Therefore,it is difficult to protect downstream areas near the river after the outburst,and personal and property safety will be greatly threatened.In order to solve the potential danger caused by dam break flood to the downstream area,better protect people’s life and property safety.This study takes the upstream construction cofferdam and the downstream construction cofferdam of Tuxikou Reservoir as the research object of dam break.MIKE software is used to establish a nested one-and two-dimensional mathematical model to analyze the mode,cause,duration and form of dam break,simulate the evolution process of dam break flood in the downstream area under different schemes,and analyze the impact results of dam break flood.To formulate flood control transfer scheme for downstream flooded areas,the following main research results are obtained through this research analysis:(1)According to the measured river surface line and river reach topography and geomorphology,through mathematical model verification,it is obtained that the value of the roughness of the river trough ranges from 0.033 to 0.04,the value of the bank roughness ranges from 0.04 to 0.50,and the value of the vegetation roughness ranges from 0.050 to 0.055,and the calibration error is within the allowable range.(2)The larger the upstream flow of the cofferdam,the higher the burst water level,the larger the peak flow of the burst;The upstream flow of the cofferdam is the same,the burst water level is the same,and the peak discharge of the burst is greater than two-thirds and greater than one-third of the total burst.The peak discharge at the bottom of the cofferdam under each scheme is far greater than the local design flood frequency.When the incoming flow is the once-per-thousand discharge and the burst water level is501m,the maximum discharge at the upstream construction cofferdam collapse is24454.701m3/s,and the maximum discharge at the downstream construction cofferdam collapse is 15245.193m3/s.(3)The maximum peak discharge and maximum flood level of outburst flood show a decreasing trend along the course;With the same inflow,the higher the outburst level,the slower the flood peak time,but the greater the peak discharge and maximum flood level.(4)The maximum flow velocity of outburst flood under each scheme is consistent with the general hydrodynamic law,and the maximum flow velocity is near the river thalweg,reaching 18.1m/s;The flow velocity of outburst flood decreases rapidly within one hour of outburst,and the flow velocity decreases slowly after one hour of outburst flood.(5)The outburst flood has a great impact on the downstream Dukou Township area.According to the analysis of the maximum submerged area of Dukou Township area under different schemes,the submerged range under each scheme ranges from 86,788m~2to 130,000 556m~2,accounting for 35.84%to 53.92%of the whole Dukou Township area.In view of the most serious inundation area,the flood control transfer scheme is formulated for the downstream areas. |
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