Analysis And Research On Spatial Distribution Efficiency Of Asymmetric Light Intensity Of Highway Tunnel

China’s tunnel and underground engineering business has been the country with the largest number of tunnels,the longest mileage and the fastest development speed in the world since the 1980s.As a special structure of the highway,the tunnel’s unique environment makes the highway tunnel need artificial lighting.According to the investigation and analysis,the power consumption of the highway tunnel lighting system accounts for about 80%of the total power consumption of the tunnel.The huge electricity cost often becomes a heavy burden for the operating enterprise,but the tunnel lighting system is also important for the drivers in the tunnel to obtain traffic information,and is also an indispensable part of the safety of highway tunnel operation.In this paper,from the perspective of improving the lighting efficiency of highway tunnels,based on the system engineering idea,the"light spatial distribution——asymmetric type——application evaluation"of the lighting source in the middle section of the tunnel is the main line of research,and the lighting quality indicators and economic benefits are the lighting efficiency evaluation standards.Experiments and numerical simulation are research methods.The specific research work includes:A brief introduction to the visual characteristics of tunnel threshold.On the basis of the driver’s visual brightness requirements,the tunnel lighting section division and lighting quality evaluation system are explained,and the small target visibility is analyzed as the driving visual evaluation.Based on the two-dimensional description of the spatial distribution of light intensity,the asymmetric light distribution of the longitudinal section of the road(C0°～180°plane)and the transverse section(C90°～270°plane)is proposed,and the horizontal and vertical directions are analyzed Illumination characteristics of asymmetric;According to the definition of the display coefficient,the asymmetric distribution of light intensity in the longitudinal direction of the road has three typical lighting types:symmetrical lighting,counter-beam and pro-beam lighting.Full-scale test and simulation of the above three types of lighting were conducted to analyze the lighting efficiency of asymmetric light distribution lighting on the tunnel cement pavement(C1type)and asphalt pavement(R3 type);based on the example tunnel model,the advantages of lighting Conduct energy-saving optimization and defect analysis,and economic benefit calculation.The study concludes:(1)The visibility of small targets in tunnels with counter-beam lighting is prominent,but the negative effects of glare(TI)are also more obvious,while pro-beam lighting has no obvious advantages.(2)When the tunnel is a general cement concrete pavement,the advantages of asymmetrical lighting compared to symmetrical lighting are not obvious.Counter-beam lighting in asymmetric lighting on asphalt pavement has a significant gain on pavement brightness.In the study conditions,counter-beam lighting has an average brightness gain of approximately 22%compared to symmetrical lighting.(3)In the analysis of pavement uniformity,the pavement material has little effect on pavement uniformity.From the perspective of experimental visual effects,the uniformity of symmetrical lighting is better than that of asymmetrical lighting.(4)Example tunnel counter-beam lighting configuration optimization and economic benefit calculation.In the TI optimization analysis,counter-beam lighting is not recommended for threshold zone.When the maximum light intensity angle of basic lighting is controlled within 40°,the greater the light angle,the higher the luminance of the road surface,but the STV will be reduced.When the basic lighting luminance level of the example tunnel is 3.5cd/m~2,counter-beam lighting saves more than 19%of energy consumption than symmetrical lighting.The long tunnel of the example tunnel section is retrofitted with counter-beam lighting,which theoretically saves at least 1 million.It is estimated that the basic lighting of long tunnels in the country can save billions of units in electricity 0.1 bills every year,and the economic benefits are significant.