青藏铁路多年冻土区普通路基热状况监测分析  

Monitoring and analyzing the thermal conditions of traditional embankments along the Qinghai-Tibet Railway

作　　者：穆彦虎[1] 马巍[1] 牛富俊[1] 李国玉[1] 王大雁[1] 刘永智[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室,甘肃兰州730000

出　　处：《冰川冻土》2014年第4期953-961,共9页Journal of Glaciology and Geocryology

基　　金：国家重点基础研究发展计划(973项目)(2012CB026106;2012CB026101);中国科学院西部之光"西部博士"项目(51Y351211)资助

摘　　要：基于现场地温监测数据,选取年平均地温不同的监测断面对青藏铁路普通路基的热状况进行分析,包括多年冻土上限变化及其地温变化、下伏多年冻土温度变化、原天然地表附近热收支等方面.结果表明:在低温多年冻土区,路基下部多年冻土上限均有所提升,且新近形成的人为上限较为稳定,冷季时负温积累显著;路基下伏多年冻土总体热稳定性较好.而在高温多年冻土区,左(阳坡)路肩下部多年冻土上限多表现为下降,右(阴坡)路肩下部多年冻土上限有升有降,但是新近形成的上限均温度较高且有进一步升温的趋势;与天然场地地温相比,路基下部多年冻土均出现一定的升温.尤其在高温极不稳定多年冻土区,天然场地多年冻土自身处于吸热升温状态;路基修筑后,下部多年冻土已经出现了融化夹层及双向退化的情况,路基热稳定性较差.对于普通路基来说,由于青藏高原强烈的太阳辐射及青藏铁路总体走向原因,普通阴阳坡效应显著,左、右路肩下部多年冻土热稳定性差异较大.Based on in-situ observed ground temperature data, some typical monitoring sites with different mean annual ground temperatures （MAGT） are selected to analyze the thermal performance of traditional earthen embankment along the Qinghai-Tibet Railway. The analyses include the variations of permafrost table, temperature conditions of underlying permafrost and heat budget of shallow soils immediately beneath the original ground sur- face. The results indicate that in regions with MAGT lower than - 1 ℃, the permafrost tables under the embank- ment have been uplifted obviously and these newly formed permafrost tables have sufficient accumulation of cold- energy during cold season. Thus the thermal performances of these embankments are satisfactory. While, in re- gions with MAGT higer than - 1 ℃, the permafrost tables under shady shoulders of the embankments all move upwards, while those under sunny shoulders move either downwards or upwards. Meanwhile, these newly formed permafrost tables beneath the embankments have slightly warming trends. Permafrost beneath the embankment is all warming slowly but progressively. In some more wanner sites, permafrost in the natural ground is in heat-absorbing stage. After the embankment construction, permafrost beneath the embankment experiences both downward and upward degradation. Additionally, due to strong solar radiation on the Tibetan Plateau and the main trend effect of the railway, difference in the thermal conditions of permafrost beneath embankment is considerable between the sunny and shady shoulders.

关 键 词：普通路基 多年冻土 热稳定性 热收支 青藏铁路 

分 类 号：U416[交通运输工程—道路与铁道工程]