Experimental Study Of LED Lighting On Comprehensive Environment Safety Of Tunnel

The improvement of tunnel lighting conditions plays a very important role in reducing tunnel traffic accident rate.In recent years,LED lamps have gradually replaced traditional lighting lamps and have been widely used in the field of tunnel lighting.However,there is no scientific evaluation method and comprehensive technical index to ensure the safety of LED lighting.Therefore,it is of great significance and value to study the safety of tunnel LED lighting in the comprehensive environment.In this paper,by means of visual performance experiment,smoke penetration experiment,real vehicle experiments and field measurement,combined with the actual luminance perception theory of human eyes,and visible light scattering theory,the visual response law and eye movement change characteristics of drivers in tunnel comprehensive environment are analyzed.The mechanism of the influence of the LED color temperature on the human eye in the process of visual adaptation is revealed,and the characteristics of the antagonistic effect of luminance level and change amplitude on actual luminance perception in the process of light dark alternation are also revealed.The smoke penetration mechanism of single and multi-color light in mountainous and urban haze environment was explored.Technical indicators such as color temperature,luminance decreasing ratio and longitudinal luminance uniformity of tunnel LED lamps that meet the safety threshold of drivers’ comprehensive visual performance are proposed.A supply and control separated tunnel dimming control distribution circuit design method for LED is proposed.The main conclusions obtained are as follows:(1)The dark adaptation process of human eyes can be divided into two stages: the early stage and middle-late stage.During the early stage,the higher the color temperature of LED light source was,the smaller the pupil area was,the lower the visual load was,and the faster the reaction times were.During the middle-late stage,reaction to the intermediate color temperature was faster,showing a relatively high visual performance and low psychological and physiological load.(2)When the enhanced lighting luminance at the tunnel entrance decreases in the form of step decrease,drivers tend to withstand greater visual operation stress and a more tense psychological state,especially in a short time when the luminance drops suddenly;However,in the form of continuous and smooth decrease of the luminance,it shows higher visual performance.increasing stepped decreasing ratio of the threshold zone can effectively alleviate the decrease of drivers’ reaction ability caused by luminance changes.(3)In the light environment in the interior zone of the tunnel,the driver’s comprehensive visual performance is affected by the luminance level and uniformity at the same time.Improving the luminance level in the interior zone is conducive to accelerating the reaction speed,but it will also cause greater stimulus of light and dark changes,forming a certain degree of antagonism.At the low uniformity level,the higher the luminance level,the worse the visual performance;At a high uniformity level,the higher the luminance,the better the visual performance.The pavement luminance uniformity design of the interior zone of the tunnel should be adapted to the luminance level.(4)The higher the smoke concentration,the light source penetration decays in the form of a power function;the higher the proportion of large particle size of smoke,the lower the penetration of light source.The difference between LED and high-pressure sodium lamp can be characterized by the equivalent smoke penetration coefficient.The smoke penetration ability of multicolor light source is determined by spectral radiation energy distribution,optical apparent efficiency function and extinction coefficient,and can be quantified by the smoke penetration efficiency factor of multicolor light which is determined only by the light source attribute.(5)A design method of power supply-control separated tunnel power distribution circuit for LED light source is proposed,and the dimming control virtual circuit is separately constructed,so as to avoid the repeated cable layout between multiple power supply circuits under the traditional power supply-control fusion distribution design method,which can effectively reduce the cable consumption and reduce the investment of lighting system.Compared with the traditional power distribution mode,the shorter the tunnel length and the lower the design speed,the higher the cable saving rate of the power supply-control separated distribution circuit.