Estimating Loss Of Life Caused By Dam Breach Based On The Simulation Of Flood Routing And Refuge Of Population At Risk

Reservoir dams bring not only huge benefits to the national economy,but also great threats to the lives and property of downstream residents.Once the reservoir crashes,the consequences will be very serious.Therefore,it is of great practical significance to analyze and study the loss of life and put forward a calculation model for accurately evaluating the loss of life caused by dam failure.Hydrodynamic factors and refuge of population have a great impact on the estimation of loss of life caused by dam breach.However,the existing evaluation model is not deep enough to study the refuge behavior of population at risk.The evaluation results have limited effect on guiding relevant departments to formulate emergency plan measures to reduce potential loss of life.Aiming at the above problems,supported by the National Natural Science Foundation of China(No.51679222,51709239),this paper puts forward a model of Estimating loss of life caused by dam breach,which based on simulation of flood routing and refuge of population at risk.So as to put forward targeted risk management and control suggestions.The main contents of this paper are as follows:(1)Put forward the calculation method of life loss.According to the fuzzy,dynamic and nonlinear characteristics of dam-break flood disaster system,as well as the principle of index selection and disaster theory,the main influencing factors of life loss are identified based on the existing research,the main influencing factors of life loss are identified;by analyzing the mechanism of life loss caused by dam break,the specific process is divided,the calculation formula of life loss is proposed,flood routing and evacuation simulation of population at risk are the key to accurately assess the loss of life(2)Simulation of flood routing caused by dam failure.Combined with HEC-RAS model,the calculation principles of constant flow and unsteady flow are explained in detail;HEC-RAS two-dimensional model is constructed from seven aspects,including initial work completion,reservoir characteristics setting,dam body and breach parameters setting,roughness setting,calculation terrain generation,boundary conditions and initial conditions setting,and dam break plan setting;through the simulation of dam break flood routing process,the downstream flow is obtained,the accurate hydrological data can provide the basis for the subsequent simulation of refuge behavior of population at risk.(3)Simulate the refuge behavior of population at risk.According to the inundation range,the number of population at risk is determined.In the form of probability distribution,the proportion of population completing preparation before evacuation in different periods is characterized;considering the characteristics of different modes of transportation,an OD matrix(Origin-destination matrix)is established in GIS to calculate the evacuation time and quantify the evacuation rate of population at risk.The water regime data and building data are superimposed and analyzed,and the damage situation of the house is judged according to the damage standard of the house,and the effective escape rate is obtained considering the difference of the effects of floods with different characteristics on the exposed population,the mortality of the exposed population was determined.(4)Engineering example simulation.Taking Luhun Reservoir as an example,according to the simulation results of flood evolution and population refuge behavior,the life loss of 14 towns in the lower reaches was evaluated.Comparing the evaluation results,the evaluation results of the other 11 townships except 3townships are consistent with the results of the existing methods;the simulation results are analyzed,the accuracy of the model is verified,and some suggestions are put forward to reduce the potential loss of life.