Rock and Soil Mechanics ›› 2021, Vol. 42 ›› Issue (1): 86-92.doi: 10.16285/j.rsm.2020.5771

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Freeze-thaw cycles-physical time analogy theory based method for predicting long-term shear strength of frozen soil

ZHANG Ze1, 2, 3, MA Wei2, ROMAN Lidia4, MELNIKOV Andrey5, YANG Xi6, LI Hong-bi6   

  1. 1. Institute of Cold Regions Science and Engineering, School of Civil Engineering, Northeast Forestry University, Harbin, Heilongjiang 150040, China 2. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China 3. Coordinated Innovation Center for Permafrost Environment and Road Construction and Maintenance in Northeast-China, Northeast Forestry University, Harbin, Heilongjiang 150040, China 4. Department of Geocryology, Faculty of Geology, Lomonosov Moscow State University, Moscow, Russia 5. Melnikov Permafrost Institute, Siberian Branch, Russian Academy of Science, Yakutsk, Russia 6. Yalong River Hydropower Development Company, Chengdu, Sichuan 610051, China
  • Online:2021-01-11 Published:2021-05-26
  • About author: ZHANG Ze, male, born in 1981, PhD, Professor, PhD supervisor, research interests: permafrost engineering and environment.
  • Supported by:
    the National Natural Science Foundation of China (41771078), the Cooperation and Exchange Project Between NSFC and RFBR (42011530083) and the Science and Technology Project of Yalong River Hydropower Development Company (YLLHK-LHA-2019006).

Abstract: Freezing and thawing processes can change the structure of frozen soil and reduce the mechanical properties, thus affecting the stability of engineering infrastructures built in frozen soil. Due to the different settings of freeze-thaw cycles, a large number of experimental results cannot be effectively compared and analyzed. In addition, estimating the soil mechanical characteristics under freeze-thaw action has also become a research difficulty. In this paper, based on the frozen soil genetic creep theory, a spherical indenter is developed, and a freeze-thaw cycle–physical time analogy method is proposed. Using the number of cycles (numbers of freeze-thaw cycles) and the duration time (physical time–minutes), we can obtain the long-term strength curve family of the frozen soil and mapping the curve family into the same stress space to achieve the normalized strength curve, and thus we can predict the long-term deformation and shear strength. Finally, two soil samples are selected for testing, and the relevant equations for predicting the long-term shear strength are obtained. This method has important theoretical significance for the comparative study on the mechanical behavior of frozen soils under freeze-thaw actions. It also has value for engineering practice and stability analysis of infrastructures built in cold regions.

Key words: freeze-thaw cycle, frozen soil mechanics, long-term frozen soil strength, time analogy method, spherical indenter