| As the center of gravity of domestic highway construction gradually shifts to the west and remote mountain areas,the number of spiral tunnels also gradually increases.Rainy and snowy weather in the area where the spiral tunnel is located under low temperature conditions results in water,snow and ice formation on the road surface of the tunnel exit.influences.Therefore,it is of great significance to determine the parameters of the spiral tunnel design stage and the safe operation in the later period to judge that the vehicle will not be out of stability under the low temperature rain and snow weather.The thesis firstly defines the spiral tunnel from two angles of the headlight illumination range and the tunnel length when the vehicle is traveling in the tunnel;based on the principle that the tunnel exit meets the recognition distance,the length of the spiral tunnel exit section is defined.By analyzing the lateral stability and longitudinal stability of the vehicle in the spiral tunnel section,the critical conditions for maintaining the stability of the vehicle in both directions are determined.Analyze the statistics of accident data in the tunnel section,and determine the high accident area in the tunnel: the section between 0m and 110 m in the opening of the tunnel.Collect the monthly average meteorological data under the low-temperature weather of the typical five-year spiral tunnel area in China,analyze and determine the climate characteristics of the spiral tunnel sections in low-temperature conditions in different areas.The impact mechanism of low-temperature rain and snow weather on road traffic was analyzed from three angles of driver,vehicle and road,and the friction coefficient measurement test was conducted to determine the variation range of friction coefficient under different rainfall intensity and icing conditions in low-temperature weather.The simulated driving simulation experiment method was adopted to carry out the simulation experiment under four conditions of normal weather,low temperature rainy day,low temperature snowy day and road freezing.Obtain the stability change law and unstable driving condition of the vehicle when it exits the spiral tunnel exit section under different weather conditions and road conditions.Regression analysis of the experimental data to obtain the relationship between vehicle driving stability and various influencing factors,which provides a reference for the subsequent research work of the exit section of the spiral tunnel.Using analytic hierarchy process combined with simulation experiment data,the importance of factors influencing the driving stability of vehicles exiting the spiral tunnel in low-temperature rain and snow weather was ranked.Finally,taking the Jin jiazhuang spiral tunnel as the research object,the stability of the tunnel when the vehicle exits the tunnel exit under low-temperature rain and snow conditions was tested,and the working conditions when the vehicle could not steadily leave the exit were determined. |
