岩土力学2026，Vol.47Issue(6)：2001-2014,14.DOI:10.16285/j.rsm.2025.1127
冻结黏土未冻水赋存状态界定与演化特征试验
Experimental study on the definition and evolution characteristics of unfrozen water retention states in frozen clay
摘要
Abstract
To address the issues of accurate conversion of the T2 spectra at different temperatures and the definition of water retention states in low-field nuclear magnetic resonance(L-NMR)unfrozen water tests,this study conducted freezing L-NMR tests on saturated and centrifuged samples.The evolution characteristics of unfrozen water under two conditions were studied,achieving an accurate conversion of T2 spectra during the freezing process and a precise delineation of the water distribution states.Building upon these insights,the migration mechanisms of unfrozen water in both states were subsequently analyzed.The main conclusions are as follows:(1)A temperature correction method for the freezing T2 spectra was developed.Using this method,the disparities in the soil freezing characteristic curves(SFCCs)between the two states were scrutinized.It was observed that the unfrozen water content in the saturated samples was consistently higher than that in the centrifuged samples.The variance in water occurrence was pinpointed as the primary contributor to this discrepancy,and the T2 threshold ranges corresponding to different water retention states were established as follows:film water(0.038-0.396 ms),capillary water(0.396-2.319 ms),and free water(≥2.319 ms);(2)Leveraging the evolutionary traits of unfrozen water and the Gibbs-Thomson effect,the surface relaxation rate ρ2=49.49 nm/ms was ascertained as suitable for this experimental context.This facilitated the transformation from T2 distribution to pore size distribution,and r=58.8 nm and r=344.0 nm were identified as the boundary pore sizes delineating film water,capillary water,and free water,respectively.(3)The experiments revealed a temperature threshold at which the migration of film water ceases in both saturated and centrifuged samples.Additionally,the temperature threshold for saturated samples was found to be higher than that for centrifuged samples.It was concluded that the migration cutoff temperature for film water is controlled by the pore water saturation in the capillaries,with samples having higher saturation showing a higher migration cutoff temperature for film water.Both saturated and centrifuged samples demonstrated temperature thresholds at which the migration of film water ceased,with the threshold for saturated samples being elevated compared to that of centrifuged samples.The cessation temperature for film water migration is governed by the pore water filling rate within the capillaries,with samples exhibiting higher filling rates displaying elevated cessation temperatures for film water migration.关键词
未冻水/水分迁移/低场核磁共振/孔隙水分布/土体冻结特征曲线Key words
unfrozen water/water migration/low-field nuclear magnetic resonance(L-NMR)/pore water distribution/soil freezing characteristic curve(SFCC)分类
建筑与水利引用本文复制引用
林键,李永恒,姚亚锋,彭世龙,吴云..冻结黏土未冻水赋存状态界定与演化特征试验[J].岩土力学,2026,47(6):2001-2014,14.基金项目
国家自然科学基金(No.52304073) （No.52304073）
安徽省自然科学基金青年项目(No.2208085QE142).This work was supported by the National Natural Science Foundation of China(52304073)and the Youth Science Fund of Anhui Provincial Natural Science Foundation(2208085QE142). （No.2208085QE142）
