Strength of frozen soils during thawing

Maslikova, O. Ya.; Debolsky, V K; Ionov, D. N.; Gritsuk, I. I.; Sinichenko, E K

doi:10.1088/1742-6596/1687/1/012039

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Taking the athletes who have reached the level of athlete in the national snowboard platform jumping team as the research object, a total of 50 athletes participated in the experiment, including 25 men and 25 men, by random selection, each group of athletes was divided into two groups according to their sports performance. 4 The basic conditions of the two groups of athletes are introduced as follows: The age range of athletes is 17.11-19.51 years old, the height range is 164.48-169.08cm, the weight range is 50.08-65.28kg, and the sports years range is 5.5-11.9 years (see Table 1).…”

Section: Research Objectmentioning

confidence: 99%

Strength Training Methods for Skiers

Liu

Wang

2023

Rev Bras Med Esporte

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Introduction: The ski jumping sequence can be divided into four steps: support, take-off, flight, and landing. Each stage has specific tasks and functions and is closely related, with the completion of each stage depending on the previous one. Objective: Explore the effectiveness of special strength training methods for ski sportsmen. Methods: Using the method of scientific literature review, expert interview, experience, and mathematical statistics to perform the special strength training for Chinese ski athletes, comparing the changes in the jump speed and take-off of the big jumps before and after 16 weeks of strength training with a specially developed protocol. Results: There were significant differences in take-off speed and air height before and after the experiment (P<0.05). The athletes in the experimental group significantly differed in takeoff speed before and after participation in the experiment (P=0.01). Conclusion: The experimental results fully evidence that by improving the rapid contraction strength of flexor and extensor muscles of the trunk and hip joints, modern abdominal center strength training methods are more effective than traditional methods. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

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Section: Research Objectmentioning

confidence: 99%

Strength Training Methods for Skiers

Liu

Wang

2023

Rev Bras Med Esporte

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Numerical Analysis of the Influence of Foundation Replacement Materials on the Hydrothermal Variation and Deformation Process of Highway Subgrades in Permafrost Regions

Shan

Guo

et al. 2022

Water

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Affected by global warming, permafrost thawing in Northeast China promotes issues including highway subgrade instability and settlement. The traditional design concept based on protecting permafrost is unsuitable for regional highway construction. Based on the design concept of allowing permafrost thawing and the thermodynamic characteristics of a block–stone layer structure, a new subgrade structure using a large block–stone layer to replace the permafrost layer in a foundation is proposed and has successfully been practiced in the Walagan–Xilinji section of the Beijing–Mohe Highway to reduce subgrade settlement. To compare and study the improvement in the new structure on the subgrade stability, a coupling model of liquid water, vapor, heat and deformation is proposed to simulate the hydrothermal variation and deformation mechanism of different structures within 20 years of highway completion. The results show that the proposed block–stone structure can effectively reduce the permafrost degradation rate and liquid water content in the active layer to improve subgrade deformation. During the freezing period, when the water in the active layer under the subgrade slope and natural ground surface refreezes, two types of freezing forms, scattered ice crystals and continuous ice lenses, will form, which have different retardation coefficients for hydrothermal migration. These forms are discussed separately, and the subgrade deformation is corrected. From 2019 to 2039, the maximum cumulative settlement and the maximum transverse deformation of the replacement block–stone, breccia and gravel subgrades are –0.211 cm and +0.111 cm, –23.467 cm and –1.209 cm, and –33.793 cm and –2.207 cm, respectively. The replacement block–stone subgrade structure can not only reduce the cumulative settlement and frost heave but also reduce the transverse deformation and longitudinal cracks to effectively improve subgrade stability. However, both the vertical deformation and transverse deformation of the other two subgrades are too large, and the embankment fill layer will undergo transverse deformation in the opposite direction, which will cause sliding failure to the subgrades. Therefore, these two subgrade structures cannot be used in permafrost regions. The research results provide a reference for solving the settlement and deformation problems of subgrades in degraded permafrost regions and contribute to the development and application of complex numerical models related to water, heat and deformation in cold regions.

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Strength of frozen soils during thawing

Cited by 2 publications

References 5 publications

Strength Training Methods for Skiers

Strength Training Methods for Skiers

Numerical Analysis of the Influence of Foundation Replacement Materials on the Hydrothermal Variation and Deformation Process of Highway Subgrades in Permafrost Regions

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