摘要
热融沟是多年冻土区常见的一类热融现象,其本身的沉陷及其侧向热侵蚀会对冻土区路基工程造成危害。随着气候变暖及人类活动的不断增加,热融沟的危害将是冻土路基工程病害防治必须面对和解决的重要问题之一。以青藏铁路现行里程K980+000处路基西侧一典型发育的热融沟为研究对象,通过对地温和变形监测的结果表明:该热融沟在两年内下沉了近15 cm,下沉速度约7～8 cm·a-1,下沉主要发生在每年8～10月。热融沟沟肩不断向沟内滑移,0.5 m深度的水平位移大约是5 cm·a-1。热融沟年平均地温高于该地区天然孔平均地温约0.5℃,热融沟每年从4月开始吸热,吸热期233 d,单位面积吸热约为3300 kJ·m-2。热融沟对附近冻土路基产生较大影响,每年侧向进入路基的热量达近70000 kJ,从而可能会导致冻土路基温度升高,稳定性降低。
Thaw grooves are common features of ice-rich permafrost landscapes,whose own settlement and lateral thermal erosion will do damage to the engineering infrastructures.With the persistent climatic warming and the influences of steadily increasing human activities,the harmfulness of the thaw grooves to frozen soil roadbed will be one of the important problems of the prevention and treatment to the frozen roadbed defects.In this study a representative thaw groove at the west side of Qinghai-Tibet Railway at K980＋000 Mileage is taken as an example to monitor the changes in ground temperatures and the deformation.Integrated analysis on the monitoring results indicates that the thaw groove in bottom subsides about 15 cm within two years（2007 to 2008）,and the average velocity is close to 8 cm·a-1.The warm season is the main period of settlement,especially from August to October.The upper layers soils at both shoulders of the thaw groove gradually glide inward the groove,and the horizontal displacement at depth of 0.5 m is about 5 cm·a-1.The mean annual ground temperature in the thaw groove is about 0.5℃ higher than that in undisturbed regions.For thermal regime of the thaw groove,the absorbing heat starts in mid April,ends in the beginning of November,and lasts about 233 days.The approximate calculation shows that the absorbing heat per unit area is about 3300 kJ per year,and about 70000 kJ heat is transported from the thaw groove to frozen soil roadbed per year.It would result in permafrost warming and decline of stability.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2011年第4期566-573,共8页
Chinese Journal of Geotechnical Engineering
基金
中科院重要方向性项目(KZCX2-YW-Q03-04)
973计划前期研究专项(2010CB434813)
国家自然科学基金杰出青年基金项目(40625004)
国家自然科学基金创新群体项目(40821001)
国家基础科学人才培养基金项目共同资助项目(J0930003/J0109)
关键词
青藏铁路
热融沟
发展特征
侧向热侵蚀
Qinghai-Tibet Railway
thaw groove
developing feature
lateral thermal erosion
