摘要
多年冻土区道路病害主要是由路基下多年冻土融化下沉引起,降低路基土体温度、保护冻土是连续多年冻土区的主要建筑原则.通过室内试验研究了在边界温度周期性波动及一定风速条件下块石层和碎石层的降温效果.结果表明:在负温及正温期结束时,块石层中温度沿深度方向是单调变化的,而在碎石层中是非单调变化的;正温结束时,块石层孔隙中的空气温度比块石表面温度低;一定厚度的块石层和碎石层均具有明显的降温效果,在相同边界条件下,平均粒径约7cm的碎石层的降温效果比平均粒径约为22cm的块石层好.因此,选择降温层的最佳粒径及厚度对实际工程具有重要意义.
Engineering troubles of railway/roadway in cold regions are mainly caused by thaw settlement of permafrost. Reducing the embankment soil temperature and maintaining permafrost is the main construction principle. Experimental models of block stone layer and crushed stone layer were set in a big modeling chamber at one time. Temperature boundary of them was vibrated periodically with constant wind speed. The experiment shows that both the block stone and the crushed stone can cool the bottom of themselves. The cooling effect of crushed stone with a mean grain size of 7 cm is better than that of block stone whose mean grain size is about 22 cm, and the temperature at the bottom of crushed stone layer at the end of the test was 3.5 ℃ lower than that of block stone layer; At the end of the negative temperature period and the positive temperature period, temperature in block stone changes monotonously from top to bottom, but it is no-monotonously in crushed stone; At the end of positive temperature, temperature of block stone layer surface is warmer than the pore-air temperature in block stone layer; A critical thickness of block stone or crushed stone is the necessary condition if they have effects of cooling. The cooling function of block stone or crushed stone can be used to prevent asymmetry thaw settlement and longitudinal cracks of embankments and maintain the stability of slopes in permafrost regions.
出处
《冰川冻土》
CSCD
北大核心
2003年第6期638-643,共6页
Journal of Glaciology and Geocryology
基金
国家杰出青年科学基金项目(40225001)
中国科学院"百人计划"项目
中国科学院知识创新工程重大项目(KZCX1 SW 04)资助
关键词
块石
碎石
降温
多年冻土
稳定性
融化下沉
permafrost
thaw settlement
cooling
stability
block stone
crushed stone
