Research On The Highway Tunnel Opening Curve Line. Index

With the support of the western region,the construction of transportation facilities in the mountainous area has been developing rapidly.A construction road in the western region,however,often fill in big dig,serious damage to environment,builder in order to avoid the happening of this situation,need to build a large number of tunnels and Bridges.For example,in the preliminary design stage,the tunnels ratio of the yaxi highway reaches 82%.Therefore,the highway tunnel will grow rapidly for a long time to come.However,with the increase of the highway construction scale,the probability of traffic accident near the tunnel in continue to rise,according to the statistics,in some sections of the chengnan highway in 2004-2006 average per kilometer 3 traffic accident occurs,the traffic accident in tunnel sections per kilometer is six times the average section,the tunnel entrance traffic accidents occupy about 60.3% of all traffic accident on the highway.Through the analysis of the traffic accident in the tunnel entrance,it is found that the special environmental factors,driving track and linear index are the main causes of traffic accidents.Therefore,the transportation sector practitioners should study the causes of tunnel portal traffic accident carefully,to conduct the thorough research to the tunnel entrance curve linear indicators,to provide the line for the safety of the indicators.This paper points out the scope of this article and analyzes the tunnel portal driver driving environment,and combining with related data on the driver's visual characteristics,the tunnel portal vehicle speed,the tunnel portal vehicle acceleration,tunnel portal of traffic accident,vehicle driving path analysis,we summary of its change rule in the tunnel mouth.It is the research of tunnel entrance curve linear index to provide theoretical basis.Secondly,through the analysis of the vehicle horizontal distance of the tunnel opening,the deviation threshold of the vehicle in the tunnel hole is obtained.Finally,through the analysis of the affecting factors to the tunnel portal circular curve radius,to establish a calculation model of the three kinds of tunnel portal circular curve radius,based on the model and the analysis of the vehicle in the tunnel mouth of the horizontal distance,we get the suggested values of tunnel portal circular curve radius;Combined with the analysis of the affecting factors of tunnel portal cyclotron lines,establish tunnel portal cyclotron line parameters of three kinds of calculation model,based on the model and the vehicle in the tunnel mouth migration threshold analysis,we get the advice of tunnel portal swing line parameter values.This article research results for the mouth of the linear curve tunnel index research provides the theoretical basis,to make up for in the specification of curve tunnel hole qualitative defects of the linear indicators,has a certain practical significance.