考虑驾驶人安全与视觉特性的高速公路路堑边坡景观优化

为了提升高速公路路堑边坡的景观效益及安全价值，提出考虑驾驶人安全与视觉特性的路堑边坡景观优化思路。首先结合驾驶人视觉特性，以行车视距、注意力集中点和最深视野为参数，对高速公路视觉敏感度进行分区研究，得到高、中、低3级视觉敏感区空间范围。其次对路堑边坡进行景观比重研究，结合净区设置规范，进行净区和景观比重数值模拟计算，得到坡率为1∶8~1∶0.75的路堑边坡在6组坡高下满足净区设计规范之后的景观坡面占据高视觉敏感区的景观比重值。最后结合模拟结果提出路堑边坡优化建议，使其在保障驾驶安全的基础上实现景观效益最大化。结果表明：车速为80 km·h^-1时，高视觉敏感区宽37 m、高10 m，中、低视觉敏感区均宽119 m、高82 m；路堑边坡坡高为0.75 m时，坡率为1∶8~1∶7的边坡景观比重可以超过50%，坡高大于3 m时，缓于1∶1.5的路堑边坡坡长占据高敏感区的景观比重接近定值71%；坡高一定时，路堑边坡坡率越缓，越容易满足净区宽度设置要求，可在增强交通安全属性的同时提升边坡景观展示效率。

Landscape Optimization of Expressway Cutting Slope Considering Driver Safety and Visual Characteristics

To improve the landscape and safety value of expressway cutting slope, an optimization idea of cutting slope landscape considering driver safety and visual characteristics is proposed. First, combined with the dynamic visual characteristics of drivers, the improved driving sight distance, focal point and farthest field of vision were taken as parameters. The visual sensitivity of the expressway was divided into zones; and the spatial range of high, medium, and low levels of visual sensitivity was obtained. Second, combined with the clear zone design specifications, the clear zone setting of the cutting slope with a slope of 1∶8 - 1∶0.75 in six groups of slope heights and the simulation test of the landscape proportion of the visual sensitive zone was carried out; and the threshold of the landscape proportion of the cutting slope in the high visual sensitive zone after meeting the clear zone design specifications was obtained. Finally, combined with the test results, the optimization suggestions of the cutting slope were submitted to maximize the landscape influence on improved driving safety. The results showed that when the speed is 80 km·h^-1, the high visual sensitive zone is 37 m wide and 10 m high, and the average width and height of the medium and low visual sensitive zones are 119 m and 82 m, respectively. When the slope height is 0.75 m, the landscape proportion of 1∶8 - 1∶7 slope exceeds 50%. Further, when the slope height is greater than 3 m, the landscape proportion of the cutting slope is less than 1∶1.5, occupying the highly sensitive zone that reached a fixed value of 71%. When the slope height is fixed, the more gentle the cutting slope, the easier it is to meet the requirements of the clear zone width setting; this facilitates the enhancement of the traffic safety attribute and increases the proportion of the slope landscape.