摘要
为了解路基填筑对路基下多年冻土热状况的影响程度,在国道214沿线典型地段设置了监测断面,在天然场地路基中心、左右路肩及左右坡脚等处布设了测温孔。采用现场监测和数值模拟相结合的方法,分析了国道214沿线路基下伏多年冻土热状况长期变化情况。研究结果表明:多年冻土区修筑普通路基以后,多年冻土地温逐渐升高,路基下多年冻土发生快速融化;开始融化的时间提前,完成回冻的时间有所延后;针对K369+210断面,左路肩、路基中心以及右路肩下8m处升温速率分别为0.040,0.050,0.047℃·年-1,人为上限下降速率分别为16.82,25.36,16.73cm·年-1;在考虑全球气温升高的情况下,多年冻土温度持续升高,路基下多年冻土处于持续退化状况;年平均地温越高,人为上限下降的幅度越大;在路基运营30年内,多年冻土上限仍处于下降状态,这将严重威胁多年冻土路基的安全运行;需要及时采取措施主动冷却路基来保护冻土,避免产生更大的融沉变形,从而保障路基正常运营。
In order to analyze the influence of embankment construction on thermal regime of permafrost underlying the embankment, monitoring sections were set along the National Highway G214. In these sections, the thermometer holes were installed at the nature ground, the centre of embankment, left and right shoulder, and left and right side of slope toe. By using the method of field monitoring and numerical simulation, the long-term changes of thermal regime of permafrost underlying embankment along the National Highway G214 were investigated. The results show that after the construction of common embankment in the permafrost region, the permafrost ground temperature gradually rises up and the melting rate of permafrost beneath the embankment is accelerated. The time of initially melting is ahead of schedule and the time of completing freeze-back is postponed. For the K369＋210 section, at the 8 m depth under the left side of road shoulder, subgrade center and right side of road shoulder, the ground temperature rises up with a speed of 0. 040, 0. 050 and 0. 047 ℃ per year respectively, and the descending rates artificial upper limit are 16. 82, 25. 36 and 16. /3 cm per year, respecL, w,y. consideration of the rising global temperature, the ground temperature gradually rises up and the permafrost underlying the embankment is in a continuous degradation situation. The artificial upper limit drops into a larger range when the average annual ground temperature is higher. After 30 years of the embankment operation, the permafrost upper limit continues to decline, which will affect the normal serving of the embankment in the permafrost regions. Thus, some measures should be adopted timely to protect permafrost by actively cooling embankment and to avoid greater thaw deformation, ensuring the normal operation of the embankment.
出处
《中国公路学报》
EI
CAS
CSCD
北大核心
2016年第11期25-32,共8页
China Journal of Highway and Transport
基金
交通运输部应用基础研究项目(2014 319 363 200)
青海省科技项目(2013-J-770)
关键词
道路工程
多年冻土
现场试验
热状况
road engineering
permafrost
field test
thermal regime
