青藏铁路低温冻土区片石路基的温度特征

在青藏铁路五道梁低温冻土区进行了片石护道路基新结构和土护道路基结构的实体工程试验，以确定路基修筑对温度场的影响．对测试断面冻融循环的地温监测资料的分析表明，2004年片石路基左右路肩孔冻土上限处，年平均地温分别低于土护道路基相应位置0．12℃和0．14℃．2005年片石路基左右路肩孔分别低于土护道路基相应位置O．65℃和0．03℃，冻土上限以下地温均呈逐年下降趋势．片石护道和土护道路基冻土上限均存在不对称性，但随着时间发展，片石护道路基最大融化深度位置基本接近或超过天然地面，且冷生过程还在继续．该区域的片石护道路基新结构能够有效发挥降低地温、主动保护多年冻土的作用．

Temperature Characteristics of Subgrade with Rock Berm in Low Temperature Frozen Ground of Qinghai-Tibet Railway

The engineering experiments of subgrade with rock or soil berm were carried out in Wudaoliang low temperature frozen ground of Qinghai-Tibet railway to examine the new style subgrade structure cooling effect on subgrade temperature field. The ground temperature monitoring result of test section after several freezing-thawing cycles showed that ground temperature in the left and the right shoulder hole of subgrade with rock berm were 0.12℃ and 0.14 ℃ lower than that of general subgrade with soil berm in 2004, and 0. 65℃ and 0.03℃ lower in 2005. The temperature below thawing-freezing depth behaved descending tendency annually. The 0℃ temperature contour was asym- metrical. As time goes on, the thawing-freezing depth of subgrade with rock berm rises near to the ground surface or above it with cold effect. The new structure style of subgrade with rock berm in this area of Qinghai-Tibet railway could reduce ground temperature and protect permafrost.