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以青海共和至玉树公路K418+462处块石路基为研究对象,分析了沥青路面铺设前、后的块石层内地温、块石层底热流密度以及路基中孔地温变化过程,研究了沥青路面对块石层内自然对流降温效应的影响。结果表明:块石层内上下温差在路面铺设后明显降低,导致路面铺设后块石层中自然对流强度降低为路面铺设前的约40%;在沥青路面强吸热以及块石自然对流强度降低的影响下,冷季块石层峰值散热强度仅为路面铺设前的14%,同时造成暖季时路基吸热期延长约40d以及路基吸热峰值强度剧烈增加,最终表现为路基下伏多年冻土出现升温现象,冻土上限在路面铺设后下降约50cm。为增强块石路基在高温多年冻土区的适用性,建议尽量减少块石上部过渡层厚度,同时引入架空层来加强冷季时块石层内自然对流降温效应。
Taking K418 + 462 blocks of stone from Qinghai Republic of China to Yushu Highway as the research object, the paper analyzes the temperature and rock bottom heat flux in the block before and after asphalt pavement laying, Influence of natural convection cooling effect in rock mass. The results show that the temperature difference between the top and bottom of the rock block is obviously decreased after the pavement is laid, resulting in the reduction of the natural convection intensity in the rock layer after paving, which is about 40% of that before the paving. The strong heat absorption on asphalt pavement and the decrease of the natural convection intensity , The peak heat dissipating intensity of rocky layer in cold seasons is only 14% before pavement pavement, meanwhile, the endothermic period of subgrade is prolonged for about 40 days and the endothermic peak intensity of subgrade is drastically increased in warm season, Soil warming occurs, the upper limit of permafrost in the pavement after laying down about 50cm. In order to enhance the applicability of block stone embankment in high temperature permafrost regions, it is suggested to minimize the thickness of transitional layer in the upper part of block stone and to introduce the overhead layer to strengthen the natural convection cooling effect in block stone layer in cold season.