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Geomechanics and Engineering
  Volume 22, Number 3, August10 2020, pages 245-254
DOI: http://dx.doi.org/10.12989/gae.2020.22.3.245
 


Effect mechanism of unfrozen water on the frozen soil-structure interface during the freezing-thawing process
Liyun Tang, Yang Du, Lang Liu, Long Jin, Liujun Yang and Guoyu Li

 
Abstract
    The interaction between the frozen soil and building structures deteriorates with the increasing temperature. A nuclear magnetic resonance (NMR) stratification test was conducted with respect to the unfrozen water content on the interface and a shear test was conducted on the frozen soil-structure interface to explore the shear characteristics of the frozen soil-structure interface and its failure mechanism during the thawing process. The test results showed that the unfrozen water at the interface during the thawing process can be clearly distributed in three stages, i.e., freezing, phase transition, and thawing, and that the shear strength of the interface decreases as the unfrozen water content increases. The internal friction angle and cohesive force display a change law of \"as one falls, the other rises,\" and the minimum internal friction angle and maximum cohesive force can be observed at -1oC. In addition, the change characteristics of the interface strength parameters during the freezing process were compared, and the differences between the interface shear characteristics and failure mechanisms during the frozen soil-structure interface freezing-thawing process were discussed. The shear strength parameters of the interface was subjected to different changes during the freezing–thawing process because of the different interaction mechanisms of the molecular structures of ice and water in case of the ice-water phase transition of the test sample during the freezing-thawing process.
 
Key Words
    frozen soil-structure interface; freezing-thawing; NMR; unfrozen water content
 
Address
Liyun Tang, Yang Du and Liujun Yang: Architecture and Civil Engineering School, Xi\'an University of Science and Technology, Xi\'an, China

Lang Liu: 1.) Energy School, Xi\'an University of Science and Technology, Xi\'an 710054, China
2.) Key Laboratory of Western Mine Exploitation and Hazard Prevention with Ministry of Education, Xi\'an University of Science and Technology, Shaanxi, Xi\'an 710054, China

Long Jin: CCCC First Highway Consultants Co. Ltd. Shaanxi, Xi\'an 710000, China

Guoyu Li: State Key Laboratory of Frozen Soil Engineering,
Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, China
 

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