中文摘要：

采用“块石模型”对青藏铁路抛石护坡路堤进行封闭边界条件和开放边界条件下的数值模拟计算,并对结果进行了比较分析.研究表明：在封闭边界条件下,冬季抛石层内部空气的运动趋势为冷空气下渗占据主导地位,夏季空气的主要运动方向为沿斜坡向上,其综合效果有利于路堤保冷.当采用开放边界条件时,抛石层内部的空气运动主要受到外界环境的影响,路堤内的温度场在很大程度上取决于环境温度的变化.因此,抛石层的铺设对于路堤的保冷效果没有封闭边界条件下明显和有效.

英文摘要：

Numerical simulations of ballast revetment under the closed and open boundary conditions are conducted using the ＂gravels model＂, in which the embankment is composed of stones and air. The simulation results are analyzed comparatively. The results show that in winter the pore-alr of the ballast revetment mainly flows downward, whereas, in summer the upward pore-air flow is dominant in the embankment. The total effect within the year is thus to cool the embankment in a long run. If the open boundary conditions are adopted, the velocity fields temperature profiles of the influenced by environment. and the corresponding embankment are mainly Therefore, when simulating the ballast revetment, the cooling effect under open boundary conditions is not more evident and effective than that under the closed boundary conditions.