寒旱区路基冻融风蚀复合侵蚀机理试验研究

EXPERIMENTAL STUDIES ON EROSION MECHANISM OF EMBANKMENTS SUBJECTED TO WIND AND FREEZE-THAW COMPOUND EROSION IN COLD AND ARID REGIONS

寒旱区路基常年受到风沙侵蚀,同时由于强烈温差变化造成路基填料因积雪融水入渗而引起冻融循环侵蚀破坏。路基会因风蚀和冻融侵蚀的复合作用引起结构损伤下抗剪强度的持续衰减。以内蒙古那-苏省际大通道锡林郭勒盟桑根达来段的风沙土填方路段为例,考虑不设边坡防护的裸边坡为最不利情况,通过冻融风蚀风洞试验研究路基在冻融循环和风蚀循环前后填料土体抗剪强度的变化规律,将路基填料土体抗剪强度的变化作为其抗复合侵蚀能力的表征,分析冻融循环侵蚀和风蚀作用对填料土体侵蚀机理的不同,以及两种不同侵蚀作用受填料含水率的影响,揭示寒旱区路基冻融风蚀复合侵蚀机理。

Wind-snow compound erosion is a combined effect of the wind, melting snow, and temperature in a natural environment, reflected in the interaction between wind erosion and freeze-thaw erosion. An embankment is subjected to wind erosion year-round, and suffered from freeze-thaw cycle erosion due to severe temperature variation driving snowmelt infiltration the filler in cold and arid regions. This research studies an unprotected embankment filled with Aeolian sandy soil located in a section of Sanggendalai in the Xilingol League, along the Inner Mongolia-Sue provincial highway. The shear strength variation of filler is analyzed before and after freeze-thaw cycles and wind erosion cycles simulated through wind erosion tunnel tests. A shear strength variation model is proposed for the characterization of compound erosion resistance. Wind and freeze-thaw erosion have different erosion mechanisms, and the influence of moisture contents on the filler is different for different erosion mechanisms. A compound erosion mechanism of wind and freeze-thaw erosion is presented through analysing the experimental results.