RESEARCH ON LONG-TERM CREEP TEST OF PERMAFROST ON QINGHAI—TIBET PLATEAU
LIU Shiwei1,2,ZHANG Jianming1,ZHANG Hu1,ZHENG Bo3
(1. State Key Laboratory of Frozen Soil Engineering,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou,Gansu 730000,China;2. Graduate University,Chinese Academy of Science,Beijing 100049,China;3. Southwest Research Institute of China Railway Engineering Co.,Ltd.,Chengdu,Sichuan 610031,China)
Abstract:In order to investigate the creep behaviour of permafrost on the Qinghai-Tibet Plateau,long-term creep tests have been performed in permafrost regions at Beiluhe basin,and static load tests were applied. Bearing plate of the platforms is buried near the permafrost table. According to the drilling data,permafrost under the bearing plates belongs to warm and ice-rich frozen soil. Thickness of compressive layer can be determined considering lithology and ice content of frozen soil,and the concept of weighted average water content is also put forwarded. By discussing the ground temperature data,it is found that,within the annual depth of ground temperature,the average temperatures of different depths under the platforms reduces year by year,which implies that frozen ground under the platforms maintains a state of heat releasing due to cooling. Experimental study of the long-term creep test indicates that,temperature variation of the compressive layer is the decisive factor for creep deformation of permafrost. When the temperature increases,the creep rate increases accordingly. Conversely,the creep rate decreases when temperature decreases. When air temperature has little influence on the temperature of compressive layer,creep equation of warm and ice-rich frozen soil can be approximately applied to predict the development of the in-situ creep deformation. The development of creep deformation of permafrost in cold regions has significant influence on long-term stability of engineering structures.
刘世伟1,2,张建明1,张 虎1,郑 波3. 青藏高原多年冻土长期蠕变变形试验研究[J]. 岩石力学与工程学报, 2012, 31(S1): 3245-3253.
LIU Shiwei1,2,ZHANG Jianming1,ZHANG Hu1,ZHENG Bo3. RESEARCH ON LONG-TERM CREEP TEST OF PERMAFROST ON QINGHAI—TIBET PLATEAU. , 2012, 31(S1): 3245-3253.
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