Study On Traffic Flow Characteristics And Its Model Of V-shaped Subsea Tunnel

As a special existing form of the tunnel,the subsea tunnel links up the traffic between the strait and the gulf.It plays an important role in regional economic,cultural and political exchanges and development.Subsea tunnel not only has the common characteristics of general highway tunnels,but also has the inherent characteristics of double slope because of its penetration into the seabed.The traffic volume of the subsea tunnel is large,the congestion phenomenon occurs frequently in the rush hour,and traffic accidents occur from time to time.At the same time,compared with open-air highway,the space of subsea tunnel is relatively closed,the structure and facilities are complex and the evacuation is difficult.Once traffic accidents occurring in the subsea tunnel,local traffic function will be easily lost,or even the entire subsea tunnel traffic paralysis,which will lead to large-scale traffic congestion.Therefore,it is of great significance to study the traffic flow characteristics of V-shaped subsea tunnel,to strengthen the relevant knowledge,and to put forward targeted schemes for preventing traffic accidents.In this paper,firstly,the research status at home and abroad was summarized,the environmental characteristics and traffic characteristics of subsea tunnel were analyzed.The special space structure,illumination environment,road surface alignment on the physical and mental effects of drivers,and the characteristics of vehicle traffic control in subsea tunnel were discussed respectively.Secondly,the V-shaped Jiaozhou Bay subsea tunnel in Qingdao was selected as the research object,and the traffic flow characteristics under different slopes were analyzed by using video surveillance data and car-following experiment.The running characteristics of V-shaped subsea tunnel traffic flow under two states of car-following and obstruction are studied respectively.The mode of influence and action of longitudinal slope factors on vehicle acceleration in subsea tunnel was analyzed.Based on this,car-following model of subsea tunnel based on maximum velocity speed was constructed.Thirdly,the danger of free lane change,forced lane change and cooperative lane change in V-shaped submarine tunnel is analyzed.Based on the analysis of the interaction mechanism between different lane change behaviors and surrounding vehicles,risk analysis modle of lane-changing in subsea tunnel based on fuzzy inference and lane-changing behavior model under the influence of longitudinal slope based on minimum safety distance were constructed.Finally,in order to provide technical support for improving the safety of subsea tunnel operation,two schemes of traffic flow control system based on traffic monitoring and vehicle collision avoidance and early warning system based on safe driving distance are designed respectively from the viewpoint of demand management of traffic flow rational allocation and accident prevention of keeping safe distance too small.