青藏铁路片石气冷路基工程试验研究

为确定青藏高原多年冻土区片石气冷路基修筑后温度场的变化过程,在青藏铁路清水河高温冻土细粒土段设计并开展了片石气冷路堤和普通路堤实体工程对比试验.基于两个测试断面的两个冻融循环的地温和变形监测资料,对比分析了片石气冷路堤与普通路堤的天然地面孔、左、右路肩孔的地温变化情况、温度场中最大融化深度的变化及路基的沉降变形情况.结果表明:片石气冷路堤体内地温寒季明显低于普通路堤段,利于积存冷量,其最大融化深度抬升幅度较大,该路基的沉降变形小于对比段.片石气冷路堤能够有效发挥降低地温、保护多年冻土的作用,是一种主动保护多年冻土的措施.

Experimental Study of Air-Cooled Riprap Subgrade of Qinghai-Tibet Railway

The experimental project of air-cooled riprap subgrade and common subgrade was designed and performed in the Qingshuihe Test Field,an area of warm permafrost with fine frozen soil along the Qinghai-Tibet Railway,to determine the temperature field of the subgrade after the railway construction.Based on ground temperature and deformation monitoring in two freezing-thawing cycles of two sections,ground temperature variations of natural hole,left and right shoulder's holes,the maximum thawing depth,and the deformation in these two kinds of subgrade were analyzed comparatively.It is revealed that the air-cooled riprap subgrade had better effect of lowing ground temperature,lifting the maximum frozen-thawing depth obviously and decreasing deformation,as compared with the common subgrade.Therefore,the air-cooled riprap subgrade was a positive frozen soil protection measure for its effectively decreasing ground temperature and protecting permafrost.