关键词: 风吹雪, 高速公路, 波形梁护栏, 模型试验, 数值模拟

Abstract:

Snowdrift is one of the most typical snow disaster forms of road traffic in Xinjiang area. Its impact on road traffic is mainly reflected in reducing driving visibility and causing traffic interruption induced by a large amount of snow on the road surface. The snowdrift disaster along the road in Xinjiang area shows the characteristics as many points， long lines and wide spread occurring with uneven distribution in time and space. Snowdrift question involves wind field， snow distribution field， temperature field and humidity field coupling， which is a very complex scientific problem. At the same time， the prevention and control of snowdrift disasters is also a practical problem that needs to be solved urgently in the construction and operation of road traffic infrastructure in cold areas. For expressways in areas of frequent snowdrift occurring， its snowdrift disaster caused by the w-beam barrier is becoming more and more obviously. But there is still a lack of in-depth research on the w-beam barrier， which is one kind of auxiliary facilities of the highway deepening the snowdrift disaster. In view of the status mentioned above and in order to explore the causes and prevention methods to snowdrift disaster by w-beam barrier， on the background of Beijing-Urumqi Expressway （G7） engineering， the field model tests of the w-beam barrier， the cable barrier and the no barrier embankment were designed. The study also combined with numerical simulation and highway field investigation and other methods in order to verify each other. In the meantime， the influence of the w-beam barrier and cable barrier on the road snowdrift disaster of the highway is studied， and the distribution law of wind field and snow field on the embankment surface with w-beam barrier and cable barrier is obtained. The results show that the snowdrift velocity increases from the foot of the embankment on the upwind side till to the w-beam barrier installed at the shoulder of or the central divider of the road. Then it moves to the road surface through the gap in the lower part of the w-beam barrier. At this time the w-beam barrier disturbs the wind field near the ground， causing a weak wind area to appear behind the beam， resulting in a large number of snow particles deposited. Especially when the lower gap of the w-beam barrier is filled with snow， the road area behind the w-beam barrier covers the driving lane with snow， which seriously affects the road capacity. While the section without setting up a barrier or setting a cable barrier is conducive to the passage of snowdrift flow. Considering the uncertainty of future climate change， in order to better prevent the impact of snowdrift on traffic operation safety， it is proposed to replace the w-beam barrier in some areas with serious wind and snow disasters with cable barrier that meet the safety requirements of expressways. Moreover， other snowdrift protection measures such as snow fences， snow barriers and snow walls can also be adopted. The research results can provide useful reference for snow removal of the expressway and new expressway construction in the windy and snow areas of Xinjiang.

Key words: snowdrift, expressway, w-beam barrier, model test, numerical simulation