【摘要】 为了考察粒径及铺设位置对多年冻土区碎石路基降温效果的影响,采用碎石、卵砾石和砂砾石三种材料在单一结构、复合结构和混合结构三种情况下,在尺寸为50 cm×50 cm×65 cm 的绝热箱体内进行了顶面气温周期性波动的一维传热试验。试验结果表明,碎石粒径为2~4 cm、4~6 cm、6~8 cm 和10~15 cm 的单一结构碎石体中均可产生自然对流机制,其中以碎石粒径为4~6 cm 的碎石体降温效果最佳。采用不同粒径的混合结构或有上覆砂砾石和卵砾石层的复合结构都将削弱降温效果。碎石体的平均温度随碎石厚度增加而降低。为充分利用自然对流机制,多年冻土区应采用单一粒径为4~6 cm 的碎石铺设路基,不应采用不同粒径的混合结构。碎石层应铺设在路基顶面。更多还原

【Abstract】 To study the influence of diameter and paving location on the cooling effect of ballast embankment, the one dimensional tests were carried out on the three materials of ballast, cobble and sandy gravel with single, compound and mixed structures in an insulated box of 50cm in length and width and 65 cm in height under the periodic fluctuation of air temperature at the top. Results show that for the single structure, the natural convection is appeared respectively in the ballast with the diameters of 2–4 cm, 4–6 cm, 6–8 cm and 10– 15 cm, among which the ballast with diameter of 4–6 cm provides the best cooling effect. For the compound and mixed structures, the cooling effects are weakened. The mean temperature of ballast is decreased with increase of its thickness. To use the mechanism of natural convection sufficiently we suggest that the ballast with the diameter of 4–6 cm could be used as filling material for the embankment in permafrost regions and the paving location should be at the top of the embankment. The compound and mixed structures of different materials, such as ballast, cobble and sandy gravel, should not be used in permafrost regions.更多还原