Analysis And Evaluation On Operation Safety Of The Long Highway Tunnel

Highway tunnel is a special section on highway,which often traffic accident happens.When the traffic accident happens,the road traffic capacity will reduce due to the occlusion of the long highway tunnel,and secondary accident will happens for more severe cases.For this reason,the problem about operation safety of long highway tunnel urgently needs to be studied.Taking Maanshan long highway tunnel as example,long highway tunnel network and traffic accident models were established with the aid of traffic simulation software VISSIM.According to the factor analysis of tunnel operation safety,countermeasures were mentioned.The methods of emergency organization and safety grade evaluation were presented for long highway tunnel.By consulting abundant documents in home and abroad,researches statuses on highway tunnel traffic accidents were reviewed.The operation safety of highway tunnel were summarized in detail.The principle,characteristics and classification of traffic simulation technology were introduced.According to the analysis of influence factor on the models with different parameters,the influence under traffic flow,proportion of the heavy cars,and the duration of the accident was revealed.The research results prove that the influence of different traffic flow on the delay time of the accident is bigger than the impact on the average queue length;the average queue length and the delay time of the accident will become bigger when the proportion of small cars is small.The influence of delay time of the accident on the average queue length and the delay time is minor.The scope of influence on traffic accident in time and space will increase with the increase of the delay time of the accident.Through the analysis of traffic guidance measures,the study indicates that when small traffic accident occurs,taking the measure of traffic split-flow at 30 meters before accident point,and speed-limited below 50 km/h can effectively increase traffic capacity;when big traffic accident occurs,it's better to open the car crossing,or open the opposite lane.Combining the characteristics of Maanshan highway tunnel,the evaluation model of highway tunnel was established.The method of fuzzy comprehensive evaluation was used to evaluate the traffic accident emergency ability of long highway tunnel.According to the assessment indicator system,the safety level of Maanshan highway tunnel was calculated.