Study Of Light Environment Optimization Of Highway Tunnel Based On Illuminance Increase And Visual Guidance

The"white hole"and"black hole"effects of highway tunnel exits and entrances greatly aggravated the driver’s psychological and psychological burdens,and the monotonous environment and lack of reference in the middle of the tunnel will also affect the driver’s visual feelings.Designing tunnel lighting in sections to strengthen the lighting at the entrance and exit and setting up sight guidance facilities inside the tunnel to enrich the references in the tunnel were carried out in China.But the designing illuminance tunnel lighting of China is lower than that of some Developed countries.The relevant regulations of tunnel sight guidance facilities are not detailed enough,and the experience component is large in engineering application.The study of the setting methods of reflective interior materials and sight guidance facilities in tunnels is helpful to improve the visual experience of drivers in highway tunnel,and has a positive significance for improving the level of tunnel safety.Firstly,the light environment of each section of the tunnel is analyzed,and it is determined that the cause of visual discomfort for the driver at the entrance,entrance and middle of the tunnel is the lack of illumination and visual reference objects.The method of setting reflective interior materials and sight guidance facilities can improve the light environment of highway tunnel.Based on the DIALux,a highway tunnel light environment simulation model is constructed,which simulates the change of the tunnel light environment when the height of reflective materials changes between 2,3,4 and 5m,and the reflectivity changes between 0.65,0.7,0.75 and 0.8 Considering the direction of the tunnel and the laying method of lamps,the average road surface illuminance E_av,the reflection increment coefficient K,the uniformity of road surface illuminance U and the unified glare rating UGR are selected as indicators.Based on analytic hierarchy process method,the weights of each indicator are determined,combined with the Topsis comprehensive evaluation method to evaluate the of reflective materials with different height and reflectivity.The best laying method of reflective materials and lamps in different sections of tunnel is determined.The driver’s visual requirements（sense of speed,distance and direction）in tunnel section is analyzed.Based on this,it is proposed to set sight guidance facilities of combination of high frequency and small size and middle frequency and size at the entrance and exit of the tunnel.This measure can guide the driver to slow down and increase the sectional illuminance of the tunnel.The combination of middle frequency and size and low frequency and big size is also proposed to improve the sense of distance and direction of the driver.In this study,the numerical simulation method is used to explore the laying method of reflective interior materials for highway tunnels that meet the needs of tunnel illumination improvement and driver vision.Based on the driver’s visual needs,a method for setting up the sight guidance facilities for the full length of the tunnel is proposed,which is helpful to improve the problem of insufficient illumination of the tunnel and the lack of reference objects,and is of great significance for improving the traffic safety level of highway tunnel.