scholarly journals Influence of Dynamic Load on Soil Moisture Field in the Process of Freeze-Thaw Cycles

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yongting Huang ◽  
Wei Ma ◽  
Donghui Xiao ◽  
Yuezhen Xu
Keyword(s):  
Water Content ◽  
Dynamic Load ◽  
Large Scale ◽  
Load Condition ◽  
High Water Content ◽  
Depth Range ◽  
Promoting Effect ◽  
Moisture Migration ◽  
Freeze Thaw ◽  
Moisture Field

Due to climate warming and large-scale engineering activities, the embankment engineering risk in the permafrost and seasonally frozen regions caused by water content change in the soil has become more and more serious. To study the moisture migration law in the embankment under the vehicle load action and periodic variation of temperature, a series of temperature-controlled model tests under the dynamic load condition were carried out, the dynamic load was imposed by an air hammer connecting a vibration plate, which was installed on the top surface of the soil, and the variation law of the temperature and moisture fields in the model was analyzed. The test results show that the moisture field in the soil sample changes obviously with the increasing freeze-thaw cycles under the no-load condition, especially after nine freeze-thaw cycles, two moisture accumulation areas appear in the range of 8–15 cm from the soil surface; the dynamic load has an inhibitory effect on the moisture migration within 5 cm below the vibration plate and has a promoting effect on the range of 10–30 cm below the vibration plate. With the increase in the number of freeze-thaw cycles, three high-water content areas are gradually formed and approximately uniformly distributed within the 10–25 cm depth range of the soil, which has an important impact on the stability of the soil. The water content of the moisture accumulation areas during freezing is greater than that during thawing under the no-load condition, while the water content of the moisture accumulation areas during freezing is less than that during thawing under dynamic load. The research results can provide references for the embankment design and disease treatment in cold regions.

Environmental impacts of a large-scale incinerator with mixed MSW of high water content from a LCA perspective

2015 ◽  
Vol 30 ◽  
pp. 173-179 ◽  
Author(s):  
Ziyang Lou ◽  
Bernd Bilitewski ◽  
Nanwen Zhu ◽  
Xiaoli Chai ◽  
Bing Li ◽  
...  
Keyword(s):  
Water Content ◽  
Environmental Impacts ◽  
Large Scale ◽  
High Water ◽  
High Water Content

Conceptual design of underground laboratory under dynamic load condition in deep copper mine

2020 ◽  
Author(s):  
Krzysztof Fulawka ◽  
Marcin Szumny ◽  
Witold Pytel ◽  
Piotr Mertuszka
Keyword(s):  
Dynamic Load ◽  
Large Scale ◽  
Load Condition ◽  
Underground Laboratory ◽  
Underground Mines ◽  
Mining Institute ◽  
Seismic Load ◽  
Copper Mine ◽  
Total Displacement ◽  
The Moment

<p>Underground laboratories, due to their unique location, are facilities with high research and educational potential. Development of old mine chambers or setting up of new mining panels designed strictly for research and educational purpose may contribute to the development of new mining technologies. One of the initiatives aimed to enhance of the underground space usage in Europe is BSUIN project conducted in the framework of INTERREG Baltic Sea Region program. At the moment there is only one underground laboratory designed fully for research and development purposes i.e. Experimental Mine Barbara lead by Central Mining Institute of Poland. But still, there are several dozen active underground mines working in Poland. Unfortunately, the large scale of the mined-out area contributes to the generation of relatively high seismicity around mining regions. Due to safety reasons management of Polish underground mines in most cases do not allow to build such a facility like underground laboratories in close vicinity of active mining works.</p><p>Within this paper, the prototype of an underground laboratory affected by additional seismic load was prepared in condition of Polish underground copper mine. Changes in total displacement and stresses around newly created chambers with use of FEM-based numerical modelling were determined. In result possibility of setting up of underground facility under dynamic load condition was determined.</p>

scholarly journals The impacts of freeze–thaw cycles on saturated hydraulic conductivity and microstructure of saline–alkali soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenshuo Xu ◽  
Kesheng Li ◽  
Longxiao Chen ◽  
Weihang Kong ◽  
Chuanxiao Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Water Content ◽  
Size Distribution ◽  
Saturated Hydraulic Conductivity ◽  
High Water Content ◽  
Soil Permeability ◽  
Freeze Thaw ◽  
Alkali Soil

AbstractStudy on the microscopic structure of saline–alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline–alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze–thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-ray diffraction, freeze–thaw cycles test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (< 0.05 μm) and micropores (0.05–2 μm) dominated the pore size distribution. Soil saturated water conductivity was closely related to its microscopic pore size distribution. As the F–T cycles progressed, soil permeability became stronger, with the reason the pore size distribution curve began to shift to the small pores (2–10 μm) and mesopores (10–20 μm), and this effect was the most severe when the freeze–thaw cycle was 15 times. High water content could promote the effects of freeze–thaw cycles on soil permeability and pore size distribution, while the increase of dry density could inhibit these effects. The results of this study provide a theoretical basis for the remediation of saline–alkali soil in the flooded area of Southwest Shandong.

Long-Term Performance Study of High Moisture Content Cohesive Soil Subgrade in Seasonal Frozen Region

2013 ◽  
Vol 405-408 ◽  
pp. 49-56
Author(s):  
Sheng Chuan Liu ◽  
Gui Ling Ding ◽  
Gang Chen
Keyword(s):  
Theoretical Analysis ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Test Field ◽  
Frozen Ground ◽  
Freeze Thaw ◽  
Long Term Performance ◽  
Term Performance

This project is aiming at the high water content clay in seasonally frozen ground region, based on the expressway program in Heilongjiang province. By applying laboratory test, field test, field monitoring and theoretical analysis, research has been proposed to understand the deformation law and long-term performance of high water content clay subgrade in freeze-thaw condition. From the comparison test of soil and soil treated with lime, road properties of high water content clay has been found out. It is a very necessary and effective method using lime to treat the high water content clay in subgrade construction. Laboratory freeze-thaw experiments uncover the strength weakening law of soil treated with lime. With theoretical analysis and numerical calculation, the interaction between clayey subgrade and pavement structure layer under effect of vehicle dynamic load is analyzed. According to this result, control standards of subgrade frost heave in seasonally frozen ground region and subgrade resilience modulus in spring have been proposed.

scholarly journals The Influence Mechanism of Freeze-Thaw on Soil Erosion: A Review

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1010
Author(s):  
Lei Zhang ◽  
Feipeng Ren ◽  
Hao Li ◽  
Dongbing Cheng ◽  
Baoyang Sun
Keyword(s):  
Soil Erosion ◽  
Water Content ◽  
Soil Structure ◽  
Large Scale ◽  
Field Experiments ◽  
Aggregate Stability ◽  
Experimental Conditions ◽  
Freeze Thaw ◽  
Freeze And Thaw ◽  
Influence Mechanism

As an important type of soil erosion, freeze-thaw erosion occurs primarily at high latitude and altitude. The overview on the effect of freeze-thaw on soil erosion was provided. Soil erosion was affected by freeze-thaw processes, as thawing and water erosion reinforce each other. Remote sensing provided an unprecedented approach for characterizing the timing, magnitude, and patterns of large-scale freeze-thaw and soil erosion changes. Furthermore, the essence of soil freeze-thaw was the freeze and thaw of soil moisture in the pores of soil. Freeze-thaw action mainly increased soil erodibility and made it more vulnerable to erosion by destroying soil structure, changing soil water content, bulk density, shear strength and aggregate stability, etc. However, the type and magnitude of changes of soil properties have been related to soil texture, water content, experimental conditions and the degree of exposure to freeze-thaw. The use of indoor and field experiments to further reveal the effect of freeze-thaw on soil erosion would facilitate improved forecasting, as well as prevention of soil erosion during thawing in regions with freeze-thaw cycles.

High-water-content graphene oxide/polyvinyl alcohol hydrogel with excellent mechanical properties

2014 ◽  
Vol 2 (27) ◽  
pp. 10508-10515 ◽  
Author(s):  
Yifu Huang ◽  
Mingqiu Zhang ◽  
Wenhong Ruan
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Cross Linking ◽  
Freeze Thaw

Boron-cross-linked graphene oxide/polyvinyl alcohol (B-GO/PVA) hydrogels with high-water-content and excellent mechanical properties are prepared by freeze/thaw and boron cross-linking methods.

Nitrous oxide production and sources in response to a simulated fall-freeze-thaw cycle

2020 ◽  
Author(s):  
Sisi Lin ◽  
Guillermo Hernandez Ramirez
Keyword(s):  
Climate Change ◽  
Water Content ◽  
Soil Water ◽  
High Water ◽  
Organic N ◽  
High Water Content ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Water Contents

&lt;p&gt;Thaw-induced N&lt;sub&gt;2&lt;/sub&gt;O emissions have been shown to account for 30-90% of N&lt;sub&gt;2&lt;/sub&gt;O emissions in agricultural fields. Due to the climate change, increased precipitatio is expected in fall and winter seasons for certain regions. As a result, this would in turn enhance the thaw-induced N&lt;sub&gt;2&lt;/sub&gt;O emissions and aggravate climate change. A mesocosm study was conducted to investigate N&lt;sub&gt;2&lt;/sub&gt;O production and sources from soils under elevated soil moisture contents in response to a simulated fall-freeze-thaw cycle. Treatments included two levels of N addition (urea versus control) and two different management histories [with (SW) and without (CT) manure additions]. Our results showed that at least 92% of the N&lt;sub&gt;2&lt;/sub&gt;O emissions during the study were produced during the simulated thawing across all treatments. The thaw-induced N&lt;sub&gt;2&lt;/sub&gt;O emissions increased with increasing soil water content. The fall-applied urea increased the soil-derived N&lt;sub&gt;2&lt;/sub&gt;O emissions during thawing, indicating an excessive mineralization of soil organic N. Compared to the CT soils, the SW soils induced more soil-derived N&lt;sub&gt;2&lt;/sub&gt;O emissions. This could be because the SW soil had more easily decomposable organic matter which was likely due to historical manure additions. Regarding to the daily primed N&lt;sub&gt;2&lt;/sub&gt;O fluxes, different soil water contents impacted the dynamics of daily priming effect. At the high water content, the soils experienced a shift in daily primed N&lt;sub&gt;2&lt;/sub&gt;O fluxes from positive to negative and eventually back to positive throughout the simulated thawing, while the soils at lower water contents underwent positive primed fluxes in general. The shift in daily primed fluxes was probably driven by the preference of soil microbes on the labile N substrates. When the microbes switched from easily to moderately decomposed substrates (e.g., from dissolved organic N to plant residuals), they started to uptake inorganic N from the soil due to a relatively high C:N ratio of plant residuals. Therefore, a net N immobilization and negative primed N&lt;sub&gt;2&lt;/sub&gt;O production occur in the short term in the soils at the high water content.&lt;/p&gt;

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