High-density polyethylene(HDPE)/chlorinated polyethylene(CPE)/poly(vinyl chloride)(PVC) ternary blends were prepared by melt blending,and the thermo-oxidative aging and ultraviolet(UV) aging properties of the ternary blends were investigated.The results showed that,compared with CPE/PVC blends,the impact strength retention rate of the HDPE/CPE/PVC ternary blends remarkably increased after thermo-oxidative aging,and the more the HDPE content,the better the thermo-oxidative aging resistance presented.Additionally,the impact strength retention rate of HDPE/CPE/PVC ternary blends was far higher than that of the CPE/PVC blends during the whole UV aging,which suggested that UV aging resistance of the CPE/PVC blends was improved significantly due to addition of HDPE.However,when HDPE content increased to 6 phr,the impact strength retention rate of the ternary blends exhibited slight decrease.The good aging resistance of the HDPE/CPE/PVC ternary blends can be contributed to formation of the stable structure during the processing.

The mechanism of the road snowdrift deposit was explained based on the hydromechanical theory, the field observations, the wind tunnel experiments and the numerical simulations. From the mechansim, a quantitative study on the road snowdrift deposit depth was performed and a mathematical model was established as well as its parameters calibration and solution approach.

文章通过对风吹雪雪害地区不同路基高度的风雪流场的观测与分析,初步掌握了公路路基高度与风雪流场的关系,确定了风吹雪雪害地区不易积雪的合理路基高度,为公路风吹雪雪害防治技术研究提供有力的科学依据。

文章以浅槽风力加速堤构成特点、空气动力学原理为依据,通过野外现场实测和室内风洞模拟实验,对获得的浅槽风力加速堤的气流场、风压、输雪效果等数值进行分析,阐明了浅槽风力加速堤的输雪机理,建立了判别浅槽风力加速堤设置合理性的数学模型。

育草蓄雪是一种适用于草原牧区新型防治公路风吹雪雪害的生物技术措施,通过增加植被高度、盖度,达到以草蓄雪、以草固雪,防治公路风吹雪雪害的目的。文章通过对内蒙古草原、青海草原、甘肃甘南草原公路两侧植被进行的大量野外实验,建立了植被盖度、高度与地表粗糙度、风雪流启动风速、移雪量等一系列数学模型,明确了育草蓄雪的作用机理。

为了防治草原公路风吹雪危害,本课题组调查了全国大部分草原牧区公路的雪害状况,通过数量化及风速流场分析,得到如下结论:(1)在草原牧区障碍物距路较近的零路堤、全路堑、迎风半路堑、背风半路堑极易形成公路风吹雪雪害;(2)路旁有障碍物的零路堤的积雪部位主要在障碍物的迎风侧和背风侧,如果离路太近极易造成公路路面积雪;(3)全路堑的积雪部位主要位于背风坡的坡脚和迎风坡的坡脚,且无论路堑走向与风向的夹角如何,都会造成路面积雪,只是积雪量、积雪部位和积雪形态不同;(4)迎风半路堑的积雪主要位于迎风坡的坡脚位置,其严重程度与迎风坡坡度,边坡坡脚距路的远近有关;(5)背风半路堑的积雪主要位于背风坡的坡脚位置,积雪形态以高大的雪檐为主,且坡脚距路越近路面积雪就越严重.