Temperature damage and constitutive model of frozen soil under dynamic loading

Zhu, Zhiwu; Kang, Guozheng; Ma, Yue; Xie, Qijun; Zhang, Dan; Ning, Jianguo

doi:10.1016/j.mechmat.2016.08.009

Cited by 63 publications

(20 citation statements)

References 12 publications

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“…Compression strength grows with strain rate in the specimens of water-saturated sand and the sand of 10% humidity. Similar results were obtained in the strain-rate range of 400−1000 s −1 for sand with different granulometric composition and density [9].…”

Section: The Experimental Setupsupporting

confidence: 85%

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Dynamic Tests of Frozen Sand Soils

Balandin

Meyer

Abdel‐Malek³

2019

PSP

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The study of the laws of contact interaction of hard and deformable impactors with frozen soils is of great scientific and applied value. In solving such problems, numerical methods are widely used. For numerically modeling the behavior of frozen soil under dynamic loading, it is necessary to use models of soil media that adequately describe their behavior at various negative temperatures, humidities and strain rates. To identify the parameters of these models, experimental studies are required for determining dynamic properties of soils at low temperatures. The paper presents the results of experimental studies of dynamic deformation of samples of frozen sand with humidities of 10% and 18%. Compression experiments were conducted using a stand implementing the Kolsky method. Deformation curves of frozen sand at a temperature of -18 °С were obtained under uniaxial stress conditions at various strain rates in the range of 400-2500 s-1. Diagrams of strength of frozen sand under uniaxial compression as a function of strain rate are constructed. The diagrams are linear for samples of different humidity in the studied range of strain rates. Maximum stresses in frozen water-saturated sand are higher than those in frozen sand of 10% humidity. With increasing strain rate, compressive strength of water-saturated sand grows faster than that of sand with a moisture content of 10%: at a strain rate of about 500 s-1, the stresses in frozen water-saturated sand, at which the samples fail, are 1.5 times higher than those in the frozen sand with a moisture content of 10%, and at a strain rate of 2500 s-1 they are 3 times as high.

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Section: The Experimental Setupsupporting

confidence: 85%

“…Evidently, it is connected with the increased content of ice that binds sand particles and the decreased free pore space. A similar phenomenon was observed for sand with a different granulometric content and density [9].…”

Section: The Experimental Setupsupporting

confidence: 81%

Dynamic Tests of Frozen Sand Soils

Balandin

Meyer

Abdel‐Malek³

2019

PSP

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“…Permafrost is defined as earth materials, including ice or organic material, that remain at or below 0 • C for at least 2 years (Permafrost Subcommittee, National Research Council of Canada, 1988;Williams and Smith, 1989). An increase in air temperatures often thermally degrades permafrost, which has widespread impacts on engineering design, construction, resource development, carbon and water cycles, and ecological protection in cold regions (Collett, 2002;Cheng and Wu, 2007;Tarnocai et al, 2009;Schuur et al, 2009;Schaefer et al, 2011;Hinzman et al, 2013;Mu et al, 2015;Zhu et al, 2016). In terms of middle-and high-elevation permafrost regions, the area of permafrost in the Qinghai-Tibet Plateau (QTP) is the largest in the world.…”

Section: Introductionmentioning

confidence: 99%

Climate warming over the past half century has led to thermal degradation of permafrost on the Qinghai–Tibet Plateau

2018

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Abstract. Air temperature increases thermally degrade permafrost, which has widespread impacts on engineering design, resource development, and environmental protection in cold regions. This study evaluates the potential thermal degradation of permafrost over the Qinghai–Tibet Plateau (QTP) from the 1960s to the 2000s using estimated decadal mean annual air temperatures (MAATs) by integrating remote-sensing-based estimates of mean annual land surface temperatures (MASTs), leaf area index (LAI) and fractional snow cover values, and decadal mean MAAT date from 152 weather stations with a geographically weighted regression (GWR). The results reflect a continuous rise of approximately 0.04 ∘C a−1 in the decadal mean MAAT values over the past half century. A thermal-condition classification matrix is used to convert modelled MAATs to permafrost thermal type. Results show that the climate warming has led to a thermal degradation of permafrost in the past half century. The total area of thermally degraded permafrost is approximately 153.76×104 km2, which corresponds to 88 % of the permafrost area in the 1960s. The thermal condition of 75.2 % of the very cold permafrost, 89.6 % of the cold permafrost, 90.3 % of the cool permafrost, 92.3 % of the warm permafrost, and 32.8 % of the very warm permafrost has been degraded to lower levels of thermal condition. Approximately 49.4 % of the very warm permafrost and 96 % of the likely thawing permafrost has degraded to seasonally frozen ground. The mean elevations of the very cold, cold, cool, warm, very warm, and likely thawing permafrost areas increased by 88, 97, 155, 185, 161, and 250 m, respectively. The degradation mainly occurred from the 1960s to the 1970s and from the 1990s to the 2000s. This degradation may lead to increased risks to infrastructure, reductions in ecosystem resilience, increased flood risks, and positive climate feedback effects. It therefore affects the well-being of millions of people and sustainable development at the Third Pole.

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“…Moreover, effects of freezing temperature, water content, and strain rate on dynamic stress-strain relationships, strength characteristic, and failure modes are studied experimentally and numerically [4][5][6][7][8]. Previous studies indicate that the dynamic compressive strength of frozen soil increases with the increase of strain rate and the decrease of freezing temperature [4][5][6]. In addition, studies show that stress state has significant effect on dynamic mechanical property of frozen soil [7,8].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Mechanical Properties and Failure Mode of Artificial Frozen Silty Clay Subject to One-Dimensional Coupled Static and Dynamic Loads

Yao

et al. 2019

Advances in Civil Engineering

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The dynamic stress-strain relationship of artificial frozen silty clay under one-dimensional coupled static and dynamic loads is obtained using modified split Hopkinson pressure bar (SHPB) equipment. The variation in dynamic compressive strength, dynamic deformation modulus, energy dissipation, and failure mode of artificial frozen silty clay with axial precompressive stress ratio are studied in this research. Experimental results indicate that the dynamic stress-strain curves under uniaxial state and one-dimensional coupled static and dynamic loads can be divided into four stages, i.e., compaction stage, elastic stage, plastic stage, and failure stage. The dynamic compressive strength, first-stage deformation modulus, second-stage deformation modulus, and absorbed energy density of artificial frozen silty clay present a trend of first increase and then decrease with the increase of axial compressive stress ratio, and the axial compressive stress ratio corresponding to the peak value is 0.7 in this test. In addition, there is a very similar effect of axial precompressive stress ratio on dynamic compressive strength and second-stage deformation modulus of artificial frozen silty clay. At 0.4 axial compressive stress ratio, spall phenomenon appears at circumferential direction and center position of the frozen soil specimen has no obvious failure. Shear failure appears at 0.7 to 0.9 axial compressive stress ratio, and the larger the axial compressive stress ratio applies, the more obvious the shearing surface appears; moreover, comminution failure mode appears at 1.0 axial compressive stress ratio.

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Temperature damage and constitutive model of frozen soil under dynamic loading

Cited by 63 publications

References 12 publications

Dynamic Tests of Frozen Sand Soils

Dynamic Tests of Frozen Sand Soils

Climate warming over the past half century has led to thermal degradation of permafrost on the Qinghai–Tibet Plateau

Dynamic Mechanical Properties and Failure Mode of Artificial Frozen Silty Clay Subject to One-Dimensional Coupled Static and Dynamic Loads

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