Research On Mechanism And Forecast Of Highway Snowdrift Hazard

Snowdrift (also called blowing snow) is distributed rather widely around the world and appears very fluently. It may not only cause obstruction to vision, but also may cause serious snow cover. It has been a difficulty for highway transportation in snowdrift area for long term. For which, long-term and large-scale of studies and researches upon the snowdrift forming mechanism, snowdrift hazards, snowdrift countermeasure and winter roads traffic technology has been carried on in those snowy developed countries since 1930s. At present, a complete snow hazards study, technical development and application system has been formed in those countries. China began to research the problems of snow cover blockage caused by road snowdrift from 1950 and several snow hazads prevention projects were constructed in many national roads and provincial roads. However, the snowdrift in the nature is the atypical two-phase flow with various relevant influence factors and is varying widely. Its rule is learnt by human being limitedly so far. Limited to economic and technical conditions, it is hard for our country to carry on extensive theoretical research and technical application like snowy developed countries. Therefore, around the urgent demands of snow hazards prevention of road construction and management problems, we mainly abstract and digest domestic and foreign research achievements, meanwhile, combing with our advantages, mainly break through some bottleneck technical problems and provide theoretical and technical supports for road design, road maintenance and traffic management in winter that are very practical and necessary.For this purpose, guided by hydromechanics theory, this paper studied mainly the followings in micro-scale (within the range of road) facing at domestic road construction, maintenance and management practice:(1) Reviewed domestic and foreign research status of the forming mechanism, prevention technology and forecasting of blowing snow hazards; summed up the theoretical and technical problems that are urgently to be solved for present road snowdrift hazards; analyzed the methodology at snow hazards research work should apply theoretical analysis, field observation,wind tunnel experiment and computer simulation technique.(2) Systemized the existing theories about road snowdrift and its forming mechanism, that is on the basis of hydromechanics, starting from analyzing snowdrift and its main influence factors, summed up and systemized the previous research results upon the snowdrift and its forming mechanism, further studied separately physical property of snow and the structural characteristics of snow cover, forming and growing process, motion, deposition, main influence factors and its influence mechanism of snowdrift,then built up a set of more completed theory architecture of highway snowdrift and its forming mechanism facing to the engineering application.(3) Researched the quantification problem of highway snowdrift depth, aiming at this hot point and difficulty in international ice-snow science research, on the basis of up-to-date international research results and starting from hydromechanics, we set forth the way of solution to quantification of snow depth,analyzed mechanic system of the forming of snow cover shapes, proposed quantification model of snow depth, gave the calibration method and proved the efficiency of such this method.(4) In order to make it easy for road construction and maintenance guidence as well as in favor of excavating optional prevention technologies and solutions, it analyzed the affection to the forming of snowdrift by roads and environmental essential factors; meanwhile, it also analyzed the corresponding prevention technologies and solutions. That is, basing on the ideal of applying general forming mechanism and theory, combing all-over the influence factors, and directly guiding snow hazard prevention, analyzed and clarified, one by one, the influence relationship between key factors with highway snowdrift such as regional climate, landforms, hypsography, highway cuts, superfine terrain of roadside, vegetation of roadside and traffic engineering facilities. In it, corresponding prevention technology and solutions are also proposed.(5) Research on the highway snowdrift hazard forecasting. Starting from the actual status of our country, it gives the strategic research way to the research of snowdrift hazard forecasting system, and discuss such key problems as forecasting methods, forecasting indexes, systemic framework of forecasting, snowdrift hazard information collection methods and forecasting model system. It provides a good reference for future development of road snow hazard forecasting system in China.