Research On Environmental Harmony Of Subgrade In Mountain Area Expressway

Based on the security and stability of subgrade, expressway’s subgrade coordination with the environment is helpful to improve the visual effect of the expressway and personal visual pleasure, as well as to improve the process of driving comfort.First of all, according to the mountainous expressway subgrade design characteristics, subgrade environmental possible visual impact is analyzed for the driver, and using the Smart Eye Pro eye movement instrument to carry out driver’s eye movement experiment.Secondly, using the Horizon plane method to divide the driving area and based on the related literature and the actual road conditions, the different areas of the fixation objects are determined; regarding the eye movement parameters, such as driver’s fixation frequency, fixation angle, fixation time, for evaluation index to analyze the characteristics of eye movement change, and use methods of mathematical statistics, regression analysis, to confirm the driver’s visual sensitive areas; Further analysis of the different regional distribution characteristics of the fixation object, mountainous expressway’s subgrade environmental visual sensitive object is determined, such as the subgrade slope protection forms, flyover, etc. Based on the theory of visual shock and expressway space enclosure, analysis characteristics of mountainous expressway subgrade environment transition sections to carry out the visual suitability indices,the visual sensitivity indices, and the corresponding evaluation standard is determined.Then, based on the driver’s eye movement changing characteristics, using the evaluation process of VRM to determine the mountainous expressway visual environment coordination evaluation indices; Combined with expressway ecological environment coordinate indices,such as local topography, geomorphology and natural environment, etc. to build up mountainous expressway subgrade environmental coordination evaluation index system. On the basis of matter-element theory, the weighted average principle is used to determine the mountainous expressway subgrade environmental coordination assessment.Finally, based on the theory of the driver’s visual shock and visual continuity theory, the identification of mountainous expressway cut slope distance is put forward, cubic spline curve is used to match the driver’s vertical visual continuous curve, the circular arc curve is fitted driver’s transverse visual continuous curve; On the basis of the theory of road space, the reasonable spacing of roadside vegetation landscape is put forward. Considering the vertical height of the roadside vegetation and road horizontal, longitudinal spacing, combination of expressway subgrade width and height of slope, different lanes of the mountainous expressway sight induced structure layout is determined, and appropriate roadside landscape design scheme is selected to induce the driver’s sight naturally. Through conducting mountainous expressway subgrade slope coordinate design simulation experiment, the driver’s viewpoint changing rule is analyzed to check out the effectiveness of the coordination technology.