首页|Change of pore water near the freezing front during soil freezing:Migration and mechanisms

Change of pore water near the freezing front during soil freezing:Migration and mechanisms

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The formation and growth of segregation ice dominate the frost heave during soil freezing,which is closely related to water migration.To analyze segregation ice during soil freezing for different soils,a freezing-thawing experiment was conducted with Lanzhou loess(LZL)and Qinghai-Tibet Plateau silty clay(QSC)using a novel layered nuclear magnetic resonance approach.During LZL freezing,the unfrozen water content first increased and then decreased with decreasing temperature near the freezing front,but decreased with decreasing temperature in other layers,whereas during the freezing of QSC,the unfrozen water content in different layers(including the freezing front)decreased with decreased temperature.Notably,the increased liquid water near the freezing front during LZL freezing was primarily adsorbed water.In addition to the temperature gradient,the squeezing action during soil freezing was another important factor affecting water migration,especially at the early stage of soil freezing.However,which of the two factors,squeezing action and temperature gradient,was the dominant one causing water migration depended on soil structure.At the early stage of soil freezing,the squeezing action had a significant effect on the water migration of LZL,but no significant effect on that of QSC.Furthermore,water accumulation of LZL near the freezing front due to squeezing action at the early stage of freezing limited the formation and growth of segregation ice.This study provided an improved understanding for ice segregation and water migration during soil freezing.

freezing-thawing experimentfrozen soilnuclear magnetic resonancephase transitionsegregation icesqueezing actionunfrozen waterwater migration

Yajun SHI、Wei MA、Lianhai ZHANG、Chengsong YANG、Fei SHANG、Cheng CHEN

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State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000(China)

University of Chinese Academy of Sciences,Beijing 100049(China)

Department of Joint NMR Laboratory for Freeze-Thaw Processes in Soils of State Key Laboratory of Frozen Soil Engineering and Suzhou Niumag Analytical Instrument Corporation,Lanzhou 730000(China)

Key Project of the Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaIndependent Foundation of State Key Laboratory of Frozen Soil Engineering,ChinaNatural Science Foundation of Gansu,China

4163063641501072SKLFSE-ZT-20210722JR5RA057

2024

10.1016/j.pedsph.2023.06.009

土壤圈(英文版)
中国土壤学会,中科院南京土壤研究所和土壤与农业可持续发展国家重点实验室

土壤圈(英文版)

CSTPCD
影响因子：0.477
ISSN：1002-0160
年,卷(期)：2024.34(4)