Optimization Of Road Network At Both Ends Of Urban Tunnel Based On Matching Evaluation

Affected by the landform,the population concentration and economic development level of each city are different.In order to connect each city group without damaging the existing road network,many cities have built a large number of urban tunnels,resulting in a large number of cross regional traffic.As an important part of urban road network,the urban road connected by two ends of urban tunnel is often high-grade urban road such as trunk road or expressway.It often undertakes the task of cross regional traffic.The congestion of urban tunnels such as river crossing channel during peak period and holidays is the reflection of relieving the mismatch between road network and channel When the urban tunnel is completed,we need to re-examine the road network and evaluate its matching.Based on the topological structure of the road network,this paper evaluates the matching degree from three aspects:the function,the structure and the particularity of the tunnel.In terms of function,the most intuitive performance of the matching degree in the road network is the supply and demand balance of the road network.All urban roads have their planning and design functions,and the matching degree means the matching degree between the actual use function and the original design function.Structurally,the traffic supply of a certain section of the road network may not meet the traffic demand at a certain period of time,but we can not think that the matching degree of the road network is not high.Because each road section constitutes the whole system of road network,the local mismatch can be achieved through the change of traffic flow distribution mode.Considering the particularity of tunnel,this paper analyzes the traffic characteristics of tunnel,and the biggest difference between tunnel and general road is its semi closed.This characteristic results in a higher probability of tunnel accidents and makes it more difficult to carry out evacuation and rescue work after accidents.In this paper,the road network reliability,supply and demand ratio coefficient and tunnel driving behavior risk are selected as evaluation indexes,and the entropy method is used to determine the weight of each evaluation index.On the basis of the evaluation of the matching degree of the road network,the bi level programming model is used.The upper level planning goal is the maximum matching degree of the road network,and the lower level model is the user equilibrium model The optimization model of the matching degree of the road network is built,and the solution method is proposed.The feasibility of the solution method is proved by the calculation of an example.The research results are applied to the optimization of the east end road network of Huizhong road tunnel in Beijing and the south end road network of hejiangtao tunnel in Hengyang City,which proves that the proposed optimization method of the two ends of urban tunnel based on matching evaluation has sufficient theoretical basis,strong operability and good practical effect.