RADIONUCLIDE PROFILES AND CARBON ACCRUAL IN PERMAFROST SOIL AT TOOLIK LAKE, ALASKA

An increasing demand for forest products incites a large number of log transportation operations, which may lead to negative consequences for the soil and the ecosystem as a whole. This paper presents a mathematical model to estimate the soil deformation and compaction processes under the influence of individual components of the skidding system, such as the forwarder, limbs, butts, and tops of tree-lengths in high latitudes, permafrost soil, and forests of the cryolithic zone. The effectiveness of the proposed model was evaluated according to experimental results. Comparative analysis showed that the calculated data differ from the experimental data by no more than 10%. The deformation of the soil by the bunch of tree-length logs occurs due to shearing processes. It has been established that the initial vertical stress exceeds the radial stress by 30–40%. The result of estimating the dependency of the shelterbelt width on the number of tree-length logs showed that the limit values for logs amount to 4–6 units for the mild, medium, and solid soil categories. The obtained results and the developed model will allow for a qualitative and quantitative assessment of the technological impact on the soil during the projecting of maps for logging operations.

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Mechanical behavior of frozen soil improved with sulphoaluminate cement and its microscopic mechanism

Scientific Reports ◽

10.1038/s41598-020-73148-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Zhenhua Yin ◽

Hu Zhang ◽

Jianming Zhang ◽

Mingtang Chai

Keyword(s):

Mechanical Properties ◽

Mechanical Behavior ◽

Soil Improvement ◽

Particle Size Analysis ◽

Frozen Soil ◽

Size Analysis ◽

Permafrost Soil ◽

Compression Tests ◽

Microscopic Mechanism ◽

Sulphoaluminate Cement

Abstract The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.

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Permafrost Hazard of MoHe-DaQing Crude Oil Pipeline

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.734-737.2659 ◽

2013 ◽

Vol 734-737 ◽

pp. 2659-2663

Author(s):

Yun Bin Ma ◽

Dong Jie Tan ◽

Hong Yuan Jing ◽

Quan Xue ◽

Cheng Zhi Zhang

Keyword(s):

Crude Oil ◽

The Other ◽

Frost Heave ◽

Permafrost Soil ◽

Buried Pipeline ◽

Soil Frost ◽

Plastic Deformations ◽

Oil Pipeline ◽

Thaw Settlement ◽

Slope Instabilities

The crude oil pipeline from MoHe to DaQing (hereafter called Mo-Da pipeline) is part of China-Russia oil pipeline. Mo-Da pipeline is the first pipeline that through high latitude cold regions of China. The pipeline is in so complicated geography environment that many kinds of permafrost hazard are easily to happen including frost heave, thaw settlement, slope instabilities, and collapse and so on. The pipeline and the permafrost act and react upon one another. On one hand, soil frost heave and thaw settlement can produce extra stresses on pipe walls, which may result in centralized stresses and plastic deformations under certain conditions, even causes pipeline faults. On the other hand, buried pipeline will disturb ambient environment and then degrade the permafrost soil and finally impact safety of the pipeline. This paper mainly introduces the permafrost hazards of Mo-Da pipeline and demonstrates some methods for monitoring the influence of permafrost.

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Research and Application of Treatment Technology for Permafrost Soil Foundation in Mohe Airport

10.1109/ichceswidr54323.2021.9656260 ◽

2021 ◽

Author(s):

Zhongjin Sun

Keyword(s):

Permafrost Soil ◽

Treatment Technology ◽

Soil Foundation

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Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700 m a.s.l.) and remote site in the central Qinghai-Tibet Plateau

10.5194/acp-2016-515 ◽

2016 ◽

Cited By ~ 1

Author(s):

Zhijia Ci ◽

Fei Peng ◽

Xian Xue ◽

Xiaoshan Zhang

Keyword(s):

High Altitude ◽

Field Experiments ◽

Tibet Plateau ◽

Permafrost Soil ◽

Remote Site ◽

Water Addition ◽

Surface Exchange ◽

Entire Study ◽

Gaseous Mercury ◽

Qinghai Tibet Plateau

Abstract. The pattern of air–surface gaseous mercury (mainly Hg(0)) exchange in the Qinghai-Tibet Plateau (QTP) may be unique because this region is characterized by low temperature, great temperature variation, intensive solar radiation, and pronounced freeze-thaw process of permafrost soils. However, air–surface Hg(0) flux in the QTP is poorly investigated. In this study, we performed filed measurements and controlled field experiments with dynamic flux chambers technique to examine the flux, temporal variation and influencing factors of air–surface Hg(0) exchange at a high-altitude (4700 m a.s.l.) and remote site in the central QTP. The results of field measurements showed that surface soils were net emission source of Hg(0) in the entire study. Hg(0) flux showed remarkable seasonality with net high emission in the warm campaigns and net low deposition in winter campaign, and also showed the diurnal pattern with emission in daytime and deposition in nighttime, especially on days without precipitation. Rainfall events on the dry soils induced large and immediate increase in Hg(0) emission. Snowfall events did not induce the pulse of Hg(0) emission, but snow melt resulted in the immediate increase in Hg(0) emission. Daily Hg(0) fluxes on rainy or snowy days were higher than those of days without precipitation. Controlled field experiments suggested that water addition to dry soils significantly increased Hg(0) emission both in short and relatively long timescales, and also showed that UV radiation was primarily attributed to Hg(0) emission in the daytime. Our findings imply that a warm climate and environmental change could facilitate Hg release from the permafrost terrestrial ecosystem in the QTP.

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Effects of freezing on soil temperature, freezing front propagation and moisture redistribution in peat: laboratory investigations

Hydrology and Earth System Sciences ◽

10.5194/hess-16-501-2012 ◽

2012 ◽

Vol 16 (2) ◽

pp. 501-515 ◽

Cited By ~ 34

Author(s):

R. M. Nagare ◽

R. A. Schincariol ◽

W. L. Quinton ◽

M. Hayashi

Keyword(s):

Water Content ◽

Active Layer ◽

Water Movement ◽

Peat Soil ◽

Soil Column ◽

Initial Period ◽

Soil Freezing ◽

Permafrost Soil ◽

Freezing Front ◽

Discontinuous Permafrost

Abstract. There are not many studies that report water movement in freezing peat. Soil column studies under controlled laboratory settings can help isolate and understand the effects of different factors controlling freezing of the active layer in organic covered permafrost terrain. In this study, four peat Mesocosms were subjected to temperature gradients by bringing the Mesocosm tops in contact with sub-zero air temperature while maintaining a continuously frozen layer at the bottom (proxy permafrost). Soil water movement towards the freezing front (from warmer to colder regions) was inferred from soil freezing curves, liquid water content time series and from the total water content of frozen core samples collected at the end of freezing cycle. A substantial amount of water, enough to raise the upper surface of frozen saturated soil within 15 cm of the soil surface at the end of freezing period appeared to have moved upwards during freezing. Diffusion under moisture gradients and effects of temperature on soil matric potential, at least in the initial period, appear to drive such movement as seen from analysis of freezing curves. Freezing front (separation front between soil zones containing and free of ice) propagation is controlled by latent heat for a long time during freezing. A simple conceptual model describing freezing of an organic active layer initially resembling a variable moisture landscape is proposed based upon the results of this study. The results of this study will help in understanding, and ultimately forecasting, the hydrologic response of wetland-dominated terrain underlain by discontinuous permafrost.

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