本文選題：鹽溶液　切入點：凍結特征曲線　出處：《巖土力學》2017年07期

【摘要】：凍結特征曲線(SFCC)是指凍土中溫度和未凍水含量之間的關系,采用核磁共振系統(tǒng)和低溫恒溫冷浴獲得了采用不同濃度Na Cl溶液飽和的黏土的凍結特征曲線。根據(jù)試驗結果分析不同濃度的孔隙溶液對凍結特征的影響規(guī)律,結果表明:隨著溶液濃度的增大,凍結特征曲線向上移動,也就是說在相同未凍水含量下,濃度越大,凍結溫度越低。這主要是因為鹽溶液引起了滲透勢能,使得孔隙水中總勢能降低,從而降低了孔隙水的冰點。在凍土中,孔隙水的凍結溫度與能量狀態(tài)有關,其中孔隙水的勢能包括基質勢能和滲透勢能,而基質勢能部分又分為毛細部分和吸附部分,滲透勢能與孔隙溶液的濃度有關。當土體中未凍水含量較低時,主要是吸附效應在起作用。此時未凍水是以吸附膜的形式吸附在土顆粒的周圍,將非飽和土的概念引入到凍土中,采用分子間作用力和吸附水膜厚度之間的關系,以描述處于吸附狀態(tài)的凍結特征曲線。結合滲透勢能來模擬不同濃度下的凍結特征曲線,與試驗數(shù)據(jù)擬合結果較好。
[Abstract]:The freezing characteristic curve (SFCC) refers to the relationship between temperature and unfrozen water content in frozen soil. The freezing characteristic curves of clay saturated with different concentrations of NaCl solution were obtained by nuclear magnetic resonance (NMR) system and low temperature constant temperature cold bath. According to the experimental results, the effects of different concentrations of pore solutions on the freezing characteristics were analyzed. The results show that the freezing characteristic curve moves upward with the increase of solution concentration, that is, the higher the concentration of unfrozen water, the lower the freezing temperature, which is mainly due to the osmotic potential energy caused by salt solution. In frozen soil, the freezing temperature of pore water is related to the energy state, and the potential energy of pore water includes matrix potential energy and permeable potential energy. The potential energy of matrix is divided into capillary part and adsorption part. The osmotic potential energy is related to the concentration of pore solution. When the content of unfrozen water in soil is low, In this case, unfrozen water is adsorbed in the form of adsorption membrane around soil particles. The concept of unsaturated soil is introduced into frozen soil, and the relationship between intermolecular force and the thickness of adsorbed water film is adopted. The freezing characteristic curve in adsorption state is described, and the freezing characteristic curve at different concentration is simulated by osmotic potential energy, which fits well with the experimental data.
【作者單位】： 桂林理工大學廣西巖土力學與工程重點實驗室;中國科學院武漢巖土力學研究所巖土力學與工程國家重點實驗室;
【基金】：國家自然科學基金(No.11502276,11372078) 廣西巖土力學與工程重點實驗室資助課題(No.13-KF-01)~~
【分類號】：TU445

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本文編號：1690594