Impact of ballast grain sizes on natural convection cooling effect of embankment in permafrost regions
SUN Binxiang 1 2, XU Xuezu 1 2, LAI Yuanming 1, WANG Shuangjie 3, ZHANG Jinzhao 3
1. State Key Laboratory of Frozen Soil Engineering CAREERI CAS Lanzhou 730000 China 2. Department of Civil Engineering Shaoxing College of Arts and Sciences Shaoxing 312000 China 3. The First Highway Survey Design Institute Ministry of Communications Xi’an 710068 China
Abstract：An experimental technique to study the cooling effect of natural convection in the embankment ballast is introduced. Various testing samples for embankment materials of ballast, pebbly gravel and sandy gravel are studied both experimentally and theoretically. The results show that, under periodically fluctuating temperature of surface, the mean Rayleigh number may represent effectively triggering natural convection in the fractured rock layer. The fractured rock layers with various grain sizes can trigger various natural convection patterns. The winter-time cooling effects of natural convection in the ballast layer increase with the increase of ballast grain sizes and are accumulated with time. Meanwhile, the heat conduction in the fractured rock layer must be considered synthetically so as to determine the optimal grain sizes of embankment ballast causing the maximum winter-time cooling effect.
孙斌祥；徐学祖；赖远明；汪双杰；章金钊；. 碎石粒径对寒区路堤自然对流降温效应的影响[J]. 岩土工程学报, 2004, 26(6): 809-814.
SUN Binxiang 1 2, XU Xuezu 1 2, LAI Yuanming 1, WANG Shuangjie 3, ZHANG Jinzhao 3. Impact of ballast grain sizes on natural convection cooling effect of embankment in permafrost regions. Chinese J. Geot. Eng., 2004, 26(6): 809-814.