Estimation of unfrozen water content of saturated sandstones using nuclear magnetic resonance,mercury intrusion porosimetry,and ultrasonic tests

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外文摘要：The unfrozen water content(UWC)is a crucial parameter that affects the strength and thermal properties of rocks in relation to engineering construction and geological disasters in cold regions.In this study,three different methods were employed to test and estimate the UWC of saturated sandstones,including nuclear magnetic resonance(NMR),mercury intrusion porosimetry(MIP),and ultrasonic methods.The NMR method enabled the direct measurement of the UWC of sandstones using the free induction decay(FID).The MIP method was used to analyze the pore structures of sandstones,with the UWC subse-quently calculated based on pore ice crystallization.Therefore,the MIP test constituted an indirect measurement method.Furthermore,a correlation was established between the P-wave velocity and the UWC of these sandstones based on the mixture theory,which could be employed to estimate the UWC as an empirical method.All methods demonstrated that the UWC initially exhibited a rapid decrease from 0 ℃ to-5 ℃ and then generally became constant beyond-20 ℃.However,these test methods had different characteristics.The NMR method was used to directly and accurately calculate the UWC in the laboratory.However,the cost and complexity of NMR equipment have precluded its use in the field.The UWC can be effectively estimated by the MIP test,but the estimation accuracy is influenced by the ice crystallization process and the pore size distribution.The P-wave velocity has been demonstrated to be a straightforward and practical empirical parameter and was utilized to estimate the UWC based on the mixture theory.This method may be more suitable in the field.All methods confirmed the existence of a hysteresis phenomenon in the freezing-thawing process.The average hysteresis coefficient was approximately 0.538,thus validating the Gibbs-Thomson equation.This study not only presents alter-native methodologies for estimating the UWC of saturated sandstones but also contribute to our un-derstanding of the freezing-thawing process of pore water.

外文关键词：

Unfrozen water content(UWC)Nuclear magnetic resonance(NMR)Mercury intrusion porosimetry(MIP)Pore structuresP-wave velocitySandstone

作者：

Fei Liu、Shibing Huang、Gang Liu、Shilin Yu

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作者单位：

School of Resources and Environmental Engineering,Wuhan University of Science and Technology,Wuhan,430081,China

Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,Wuhan University of Science and Technology,Wuhan,430081,China

基金：

National Natural Science Foundation of ChinaHubei Provincial Natural Science Foundation of Chinaand"The 14th Five Year Plan"Hubei Provincial advantaged characteristic disciplines(groups)project of Wuhan University of Science

项目编号：

423771912021CFA0942023A0303

出版年：

2024

DOI：

10.1016/j.jrmge.2024.02.026

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(9)