Research On The Characteristics Of Typical Accidents And Prevention&control Technology In Road Tunnel

In recent years,with the increase of tunnel mileage,serious accidents with man death and casualty happen now and then,therefore,the safety of road tunnel operation faces a severe test.Based on the existing problems and shortcomings in the research of road tunnel safety technology,research was carried on in the following aspects in this thesis.Taking the road tunnel operation management system as the object,based on the theory of energy accidental release model and safety system engineering,the traffic safety evaluation index system is established from the analysis of the accident cause.In order to take into account the dynamics,fuzzinees and conflict among the indexes of evaluation index system,This thesis studies the comprehensive evaluation method of traffic safety integrated cloud model and improved DSmT theory.The results show that the method avoids the problem of being too dependent on the subjective weight assignment,reduces the constraint ability and conflict of the evaluation indexes,the evaluation results can better reflect the actual operation safety of the tunnel.Taking tunnel group in Luoyuan-Changle section of Shenyang-Hainan highway as the object,the characteristics of traffic accidents are studied by means of traffic accident statistics and traffic flow investigation.The research shows road tunnel traffic accidents occur quite regularly in the development trend,time distribution,accident type,accident cause,tunnel length,weather factors and so on.It reveals the deep causes of road tunnel traffic accidents are that the actual capacity of road tunnel is insufficient and service level is low.This thesis studies the prediction method of road tunnel traffic accident,establishes the comprehensive prediction model of traffic accident based on BP neural network and the autoregressive short time traffic forecasting model based on wavelet decomposition.When fire breaks out in the tunnel,the back-layering length of thermal smoke,the temperature decay rate of upstream thermal smoke and the length of the flame are the most important parameters that affect the safe escape of the trapped people.A series of small-sized tests based on the 1/20 scale tunnel model to study the influence of tunnel section size,longitudinal ventilation velocity on the characteristics of tunnel large fire that flame impact ceiling and construct an empirical model.Research shows:1)The larger the cross-sectional area of the tunnel is,the longer the back-layering length is;with the increase of longitudinal ventilation velocity,the back-layering length decreased obviously.2)Upstream thermal smoke temperature under the ceiling increases with the increase of tunnel cross-section area,and decreases with the increase of vertical wind speed.3)The length of the flame decreases with the increase of the section area of the tunnel;with the increase of longitudinal ventilation velocity,the flame length decreased obviously.According to the catastrophe characteristics of traffic flow,this thesis studies the classification warning model of traffic accident based on cush catastrophe theory,construts a traffic accident warning system and its modified model based on traffic flow parameters as the main warning index,then establishes the road tunnel traffic accident prevention system and the classification of warning response measures.The emergency technology of tunnel fire accident is studied.The back-layering length and the temperature distribution of upstream thermal smoke as well as the flame length are determined by the tunnel fire characteristic model,the PyroSim fire simulation software and the Pathfinder evacuation software are used to simulate the evacuation strategies.Research shows that,rely on the principle of proximity and the herd mentality,the people in the upstream of the tunnel fire abandoned the car and choose the cross gallery of downside of the tunnle to escape is often unsafe,the reasonable escape strategy should be developed and guided so as to improve the efficiency and success rate.Finally,the emergency rescue organization system and emergency measures of road tunnel fire accidents are studied.