摘要
根据青藏高原不同年平均地温区域多年冻土的长期监测资料及附面层理论,分别建立整体式和分离式路基计算模型,分析气候变暖和工程活动作用下多年冻土的变化过程。考虑采用分离式路基来弱化宽幅整体式路基所引起的“聚热效应”,分析不同年平均地温和隔离带宽度下分离式路基对多年冻土的影响。研究结果表明:与窄幅路基相比,宽幅路基具有强烈的吸热特性,导致下部多年冻土退化严重。在路基修筑后第50年,年平均地温为-0.5,-1.0,-1.5和-2.0℃区域的宽幅路基中心下部多年冻土上限比窄幅路基的分别低2.73,3.66,3.67和2.60 m,宽幅路基下部6 m深度多年冻土地温比窄幅路基的分别高0.61,0.87,0.82和0.48℃;两幅分离式路基之间存在相互热干扰作用,使得路基两侧土体温度场呈现明显的不对称性;随着年平均地温的降低和隔离带宽度的增加,路基两侧土体温度场的不对称性逐渐减弱,即两幅路基之间的相互热干扰作用减小。因此,拟建青藏高速公路可使用分离式路基来代替整体式路基进行修筑,且年平均地温和隔离带宽度是分离式路基修筑所要考虑的重要因素。
Based on the adherent layer theory and the long-term monitoring data of different permafrost regions in the Qinghai-Tibet Plateau,numerical models with an integral and two separated embankments were proposed and the influences of climate warming and embankments construction on permafrost were analyzed.Considering the use of two separated embankments to weaken the gathered heat effect of an integral embankment,the influence of separated embankments on permafrost zones was analyzed under the condition of different annual mean ground temperatures and separating strip widths.The results show that compared with the narrow embankment,the wide embankment has a strong heat absorption,which leads to serious permafrost degradation beneath the wide embankment.After 50 years of embankment construction on permafrost zones with annual mean ground temperature of-0.5,-1.0,-1.5 and-2.0℃,permafrost tables beneath the centerline of wide embankment are 2.73,3.66,3.67 and 2.60 m lower than those of narrow embankment,and ground temperatures of permafrost beneath the 6 m depth of wide embankment are 0.61,0.87,0.82 and 0.48℃warmer than those of narrow embankment,respectively.The mutual thermal disturbance between two separated embankments leads to the asymmetry of temperature fields beneath both sides of separated embankment.The asymmetrical distribution gradually decreases with the decrease of annual mean ground temperature and the increase of separating strip width,which means the mutual thermal disturbance between two separated embankments weakens.Thus,it is suggested that the Qinghai-Tibet expressway should be constructed with two separated embankments rather than an integral embankment,and the annual mean ground temperature and separating strip width are important factors to be considered for the construction of two separated embankments.
作者
栗晓林
马巍
穆彦虎
牛永红
黄永庭
柴明堂
LI Xiaolin;MA Wei;MU Yanhu;NIU Yonghong;HUANG Yongting;CHAI Mingtang(State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2020年第2期420-432,共13页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(41630636,41772325)
冻土工程国家重点实验室自主立项课题(SKLFSE-ZY-17)
中国科学院国际合作局对外合作重点项目(131B62KYSB20170012)~~
关键词
青藏高速公路
整体式路基
分离式路基
年平均地温
隔离带宽度
多年冻土
the Qinghai—Tibet expressway
integral embankment
separated embankment
annual mean ground temperature
separating strip width
permafrost zones
