Study on the artificial control od snow on roads

只有在充分了解道路冰雪物理特性的基础上，才能做好冬季冰雪地区交通道路的管理和养护。然而，即使是雪和冰的分类，结构和性质也没有详细研究。本研究旨在系统地测量道路冰雪的结构和物理性质，并提出一种新的分类，主要调查项目包括结构、物理性质、消失过程和热平衡。结果表明：1）道路冰雪的结构和物理性质不仅受气象条件的影响，而且受过往车辆和除雪等人为因素的影响，其结构和物理性质随时间和地点而变化; 2）道路冰雪可分为7种类型：新雪、碎雪、粉雪、颗粒雪、雪泥、冰壳和冰膜。然后，除粉雪和雪泥外，五种类型中的每一种都分为两个小类：干的和湿的。此外，干燥的积雪被细分为软的和硬的。将道路冰雪分为13种类型。3）道路上干燥的新雪迅速密实成积雪，其最大密度为500至550 kg/m^34）硬雪（600-800 kg/m^3），路面积雪融水渗透并重新冻结时，经常形成冰壳5）道路积雪表面的热量平衡与融化和消融过程密切相关。研究表明，净辐射和地表反射率是决定路面热状况的重要因素，车辆污染和积雪融化引起的反射率变化增加了积雪的消融和融化，是形成车辙的主要原因。

The proper control and maintenance of traffic roads in winter seasons in snowy areas can be accomplished only on the base od enough knowledge of physical properties of snow and ice on roads. However, even the classification, structures and properties of snow and ice have not been investigated in detail. This study was aimed at measuring systematically the structures and physical properties and proposing a new classification of snow and ice on roads; the main items of investigation are structures, physical properties, disappearing process, and heat balance. Obtained results are as follows1)The structures and physical properties of snow and ice on roads are strongly affected not only by meteorolgical conditions but also by artificial effects such as passing vehicles and snow removal; therefore the structures and properties are variable as the time and local points2)Snow and ice on roads are classified into seven types: new-snow, compacted-snow, powder-snow, grain-snow, slush, ice-crust, and ice-film. Then each of the five types except the powder-snow and slush, is divided into two subtupes; dry and wet. In addition the dry compacted-snow was subdibided into soft and hard ones. In total snow and ice on roads are classified into 13 types3)Dry new snow on roads is quickly densified into compacted-snow, the maximum density of which is from 500 to 550 kg/m^34)Hard compacted-snow(600-800 kg/m^3) and ice-crusts are often formed when melt water of the surface of road snow penetrates and refreezes in it5)The heat balance on the surface of snow on roads is colsely related to the melt and ablation process. The present study showed that the net radiation and surface albedo are the most important components to determine the heat blance both the contamination by vehicles and reflectance change due to melting increase the ablation and melt of snow, which is the main cause of the formation of ruts.